AGRICULTURAL ENGINES.
The late Mrs. Trevithick said "that during the difficulties in London
in 1808 and 1810, when Trevithick was overwhelming himself with new
experiments and the cost of patents, and law expenses, lawyers and
bailiffs took everything worth having from her house, including
account-books, drawings, papers, and models, which she never saw again."
His earlier account-books left in safety in his Cornish home, though
very disconnected, give trustworthy traces of his work up to 1803. From
that time only detached accounts or papers are found until 1812, when
the unused pages in two old mine account-books of his father served
as his letter (rough-draft) books; and judging from their number and
style, his correspondence was most extensive and varied.
[Rough draft.]
"HAYLE FOUNDRY,
_February 13th, 1812_.
"TO SIR CHRISTOPHER HAWKINS, Baronet.
"Sir,--I now send you, agreeable to your request, a plan and
description of my patent steam-engine, which I lately erected on
your farm for working a thrashing mill. The steam-engine is equal in
power to four horses, having a cylinder of 9 inches in diameter. The
cylinder, with a moderate heat in the boiler, makes thirty strokes in
a minute, and as many revolutions of the fly-wheel, to every one of
which the drum of the thrashing mill (which is 3 feet in diameter)
is turned twelve times. The boiler evaporates 9 gallons of water
in an hour, and works six hours without being replenished. The
engine requires very little attention--a common labouring man easily
regulates it.
[Illustration: TREVITHICK'S HIGH-PRESSURE STEAM-PUFFER THRASHING
ENGINE, 1812.]
"The expense of your engine of 4-horse power, compared with the
expense of four horses, is as follows:--
£ _s._
Original cost of the steam-engine 80 0
Building material and rope 10 0
------
£90 0
------
Interest on the above 90_l._ at 5 per cent. 4 10
Wear and tear at 5 per cent. 4 10
------
9 0
------
Original cost of horse machinery for four horses £60 0
Interest on the above at 5 per cent. 3 0
------
Wear and tear at 15 per cent. 9 0
------
12 0
"Two bushels or 164 lbs. of coal will do the work of four horses,
costing 2_s._ 6_d._
"Four horses at 5_s._ each, gives 20_s._ Cost of coal, 2_s._ 6_d._ as
compared with 20_s._ for horses.
"I remain, Sir,
"Your obedient servant,
"RICHARD TREVITHICK."
"CORNWALL,
_February 20th, 1812_.
"Having been requested to witness and report on the effect of steam
applied to work a mill for thrashing corn at Trewithen, we hereby
certify that a fire was lighted under the boiler of the engine five
minutes after eight o'clock, and at twenty-five minutes after nine
the thrashing mill began to work, in which time 1 bushel of coal was
consumed. That from the time the mill began to work to two minutes
after two o'clock, being four hours and three-quarters, 1500 sheaves
of barley were thrashed clean, and 1 bushel of coal more was consumed.
We think there was sufficient steam remaining in the boiler to have
thrashed from 50 to 100 sheaves more barley, and the water in the
boiler was by no means exhausted. We had the satisfaction to observe
that a common labourer regulated the thrashing mill, and in a moment
of time made it go faster, slower, or entirely to cease working. We
approve of the steadiness and the velocity with which the machine
worked; and in every respect we prefer the power of steam, as here
applied, to that of horses.
(Signed) "MATTHEW ROBERTS, Lamellyn.
"THOMAS NANKIVILL, Golden.
"MATTHEW DOBLE, Barthlever."
This first high-pressure steam thrashing machine was working on the
13th February, 1812, at Trewithen, the property of Sir Christopher
Hawkins, as proved by Trevithick's drawing of the machine, his account
of the work performed, and the report of the three wise men that the
power of steam was preferable to the power of horses. Its first cost
was less than that of a horse machine; but to make the calculated
amounts come right Trevithick charged 15 per cent. for wear and tear
on the horse machinery, and but 5 per cent. on the steam-engine;
overlooking the cost of the horses, which would have made the outlay
for the horses and machinery greater than for the steam-engine.
The whole design evidences simplicity and consequent cheapness; no
complication of valves or valve-gear, no cylinder cover, parallel
motion, guide-rods, or air-pump, with its condenser and injection-water.
The 4-horse engine, with boiler complete, cost 90_l._ A common labourer
worked it, and as it needed no supply of feed-water during six hours
of work, the cost and attention of supplying feed were avoided. If a
supply was required during the day it could be given by a pipe with two
taps.
This first use of steam in agriculture was immediately followed by
Lord Dedunstanville of Tehidy, Mr. Kendal of Padstow, and Mr. Jasper
of Bridgenorth. Sir Charles' request for a more official report signed
by disinterested persons brought a reply that the thrashing engine
continued to work well. "It far exceeds my expectation. I am now
building a portable steam-whim, on the same plan, to go itself from
shaft to shaft." "If you should fall in with any West India planter
that stands in want of an engine, he may see this at work in a month,
which will prove to him the advantage of a portable engine to travel
from one plantation to another. The price complete is 105_l._"[10]
[Footnote 10: See Trevithick's letter, 10th March, 1812, chap, xx.]
"DEAR SIR,
"ARGYLE STREET, _19th March, 1812_.
"I am sorry it is not convenient for me to advance you the money for
Wheal Liberty; adventurers having the dues very low, ought to furnish
the needful. I am very glad you have succeeded with your portable
steam-engine, and am persuaded they will be more and more adopted.
I have shown your account of your thrashing by steam, and Sir John
Sinclair and Mr. ---- very highly approve it. Sir John Sinclair wished
the communication had been made to the Board of Agriculture. Sir John
wished me to transmit you the enclosed on coals moved by steam ...
whether you had a plan of this sort, as they would be very serviceable
in passing the friths in Scotland. He seems to think you ought to
advertise your steam-engines for thrashing; indeed, I think so too.
"By the enclosed letter, Sir John Sinclair wishes you to send him an
account of your improved steam-engines. You will be careful in drawing
up your letter to Sir John, because it will probably be read to the
Board of Agriculture, and perhaps inserted in their publication. You
will begin by acknowledging his letter, of date ... respecting the
American passage boat ... and your improved small steam-engine. You
will give him an account of the saving you have effected at Dolcoath,
and a certificate of the same by the mining captains; the engine for
thrashing you built for me, and the work it did, and the coals it
consumed; the expense of the steam-engines, and the uses they may be
applied to.
"I remain, dear Sir,
"Yours most obediently,
"C. HAWKINS."
In 1812 Trevithick advertised the use and sale of steam-engines,
weighing 15 cwt., costing 63_l._, for thrashing, grinding, sawing, or
other home work; and also a more powerful engine for the steam-plough,
or the harrow and spade machine for 105_l._, to travel from farm to
farm. He wrote to Sir John Sinclair:[11]--
"I received from Sir Charles Hawkins a copy of Dr. Logan's letter to
you, also a note from you to Sir Charles Hawkins, both respecting
the driving boats by steam; respecting the engine for thrashing,
chaff-cutting, sawing, &c. I am now making one of about two-thirds
the size of Sir Charles Hawkins', which will be portable on wheels.
By placing the engine in the farm-yard, and passing the rope from the
fly-wheel through the barn-door, or window, and around the drum on the
machine axle, it may be driven.
[Footnote 11: See Trevithick's letter, 26th March, 1812, chap. xv.]
"The steam may be raised, and the engine moved a distance of two
miles, and the thrashing machine at work, within one hour.
"The weight, including engine, carriage, and wheels, will not exceed
15 cwt.; about the weight of an empty one-horse cart.
"The size is 3 feet diameter, and 6 feet high. If you wish to have one
of this size sent to the Board of Agriculture as a specimen, the price
delivered in London will be sixty guineas."
This engine differed from that referred to in the drawing of Sir
Charles Hawkins, mainly in the boiler having the fire-place in the
fire-tube, requiring no brickwork, and having the advantage of
portability. It was very like the earlier locomotive boiler, except
that it was placed upright, as steam-cranes now use boilers, instead of
being horizontal.
[Rough draft.]
"CAMBORNE, CORNWALL,
_April 26th, 1812_.
"TO SIR JOHN SINCLAIR.
"I have your favour of the 4th instant, informing me that you had sent
my letter respecting propelling ships by steam to the Navy Board; and
also requesting a drawing and statement of the thrashing engine to
be sent to the President of the Board of Agriculture, which shall be
forwarded immediately.
"I beg to trouble you with a few wild ideas of mine, which perhaps may
some future day benefit the public, but at this time remain buried,
for want of encouragement to carry it into execution.
"The average consumption of coals in large steam-engines is about 84
lbs. (or one bushel), to lift 10,000 tons of water or earth 1 foot
high.
"The average cost of this coal in the kingdom is sixpence. The average
of a horse's labour for one day is about 4000 tons lifted 1 foot high,
costing about 5_s._
"A man's labour for one day is about 500 tons lifted 1 foot high,
costing 3_s._ 6_d._
"I have had repeated trials of the water lifted by coals, horses,
and men, proving that where a bushel of coal can be purchased for
sixpence, that sixpence is equal to 20_s._ of horse labour, and to
3_l._ 10_s._ of men's labour.
"If you calculate a man to lift 500 tons 1 foot high, it is equal to
100 tons lifted 5 feet high; a very hard task for a man to perform in
a day's work.
"This calculation proves the great advantage of elemental power over
animal power, which latter I believe can in a great part be dispensed
with if properly attended to, especially as we have an inexhaustible
quantity of coals.
"To prove to you that my ideas are not _mere_ ideas, in general my
wild ideas lead to theory, and theory leads to practice, and then
follows the result, which sometimes proves of essential service to the
public.
"About six years ago I turned my thoughts to this subject, and made a
travelling steam-engine at my own expense to try the experiment.
"I chained four waggons to the engine, each loaded with 2-1/2
tons of iron, besides seventy men riding on the waggons, making
altogether about 25 tons, and drew it on the road from Merthyr to the
Quaker's-yard (in South Wales), a distance of 9-3/4 miles, at the rate
of four miles per hour, without the assistance of either man or beast,
and then, without the load, drove the engine on the road sixteen miles
per hour.
"I thought this experiment would show to the public quite enough to
recommend its general use; but though promising to be of so much
consequence, has so far remained buried, which discourages me from
again trying, at my own expense, for the public, especially when my
family call for the whole of my receipts from my mining concerns for
their maintenance.
"It is my opinion that every part of agriculture might be performed
by steam; carrying manure for the land, ploughing, harrowing, sowing,
reaping, thrashing, and grinding; and all by the same machine, however
large the estate.
"Even extensive commons might be tilled and effectually managed by a
very few labourers, without the use of cattle.
"Two men would be sufficient to manage an engine, capable of
performing the work of 100 horses every twenty-four hours; requiring
no extensive buildings or preparations for labourers or cattle, and
having such immense power in one machine as could perform every part
in its proper season, without trusting to labourers.
"I think a machine that would be equal to the power of 100 horses
would cost about 500_l._
"My labour in invention I would readily give to the public, if by a
subscription such a machine could be accomplished and be made useful.
"It would double the population of this kingdom, for a great part of
man's food now goes to horses, which would then be dispensed with, and
so prevent importation of corn, and at a trifling expense make our
markets the cheapest in the whole world; because there are scarcely
any coals to be found except in England, where the extreme price, duty
included, does not exceed 2_s._ per bushel.
"I beg your pardon for having troubled you with such a wild idea, and
so distant from being carried into execution; but having already made
the experiment before stated, which was carried out in the presence
of above 10,000 spectators, who will vouch for the facts, I venture
to write to you on the subject, for the first and only self-moving
machine that ever was made to travel on a road, with 25 tons, at four
miles per hour, and completely manageable by only one man, I think
ought not to be dropped without further experiments, as the main point
is already obtained, which is the power and its management.
"Your most obedient servant,
"RICHARD TREVITHICK."
The Board of Agriculture in 1812 had their attention drawn to the
feasibility of using the steam-engine to save agricultural labour and
lessen the cost of working land. Trevithick's intuitive knowledge told
him his application would be in vain, though an engine was at work
proving the saving of horse-power in the item of thrashing corn.
"I beg to trouble you with a few wild ideas of mine, which _perhaps may
some future day benefit the public_."
A steam-engine could exert as much power by the consumption of 6_d._
worth of coal as could be given by 20_s._ of horse-power, or by 70_s._
worth of men's power.
"Ideas lead to theory, theory leads to practice, then follows the
result, which sometimes proves of essential service to the public."
"It is my opinion that every part of agriculture might be performed
by steam. Carrying manure for the land, ploughing, harrowing, sowing,
reaping, thrashing, and grinding; and all by the same machine, however
large the estate."
"Two men would manage an engine capable of performing the work of 100
horses."
Such a use of the steam-engine, judiciously managed, "would double the
population of this kingdom, and make our markets the cheapest in the
world; because England is the country best supplied with coal and iron
for steam-engines, and the land now growing food for horses would be
available for man."
Its cost would be 500_l._, and its power sufficient to propel
the largest subsoil ploughs and tormentors; and had the Board of
Agriculture supplied such a sum of money as is now ordinarily given
by a farmer for a steam-plough, we should have had in 1812 ploughing,
harrowing, sowing, reaping, &c., by steam. Years before, the same kind
of engine had been made to work pumps, wind coal from shafts, drive
rolling mills, tilt hammers, and steamboats, and convey material from
place to place; and why should not his promise to the farmer be also
made good with his increased knowledge derived from eight years of
active experience? Receiving small encouragement in England, he applied
to sugar-cane planters to give his engines a trial in the West Indies.
[Rough draft.]
"SIR CHARLES HAWKINS, Bart.,
"CAMBORNE, _1st May, 1812_.
"Sir,--I have your favour of the 27th April, respecting a steam-engine
for your friend for the West Indies, of the power of ten mules
employed at one time. This power we calculate equal to forty mules
every twenty-four hours, as six hours' hard labour is sufficient for
one mule for one day.
"The expense of an engine of this power complete delivered in London
would be 200_l._ The consumption of coals about 84 lbs., or one
bushel, to equal the labour of three mules, or from 13 to 14 bushels
of coal every twenty-four hours to perform the full work of forty
mules (or in proportion for a lesser number), with a waste of about 15
gallons of water per hour, unless a reservoir was made to receive the
steam, and then to work the same water over again.
"Where water is scarce, nearly the whole may be saved.
"You remarked that the rope might slip round the notch in the wheel;
but to prevent any risk of that kind, I apply a small chain instead of
the rope, which works the same as a chain on the barrel of a common
thirty-hour clock.
"The speed of the periphery of the fly-wheel is about eight miles per
hour, which I think is nearly double the speed of the mules when at
work in the mill. This would reduce the size of the part which carries
the chain on the cattle mill to half the diameter of the present walk
of the cattle, which might be done without altering or interfering
with the present cattle mills, and might, if required, either work
separately or in conjunction with the mules in the same mill at the
same time.
"To inform your friend of the power and effect of such an engine, I
prefer his sending some person down to Cornwall, to see it tried on
some of the cattle mills or whims in the mines.
"Engines that have been sent to the West Indies hitherto have cost
nearer 2000_l._; very large, heavy, and complicated machines,
requiring 2500 gallons of water per hour for condensing, and could
only be managed by a professed engineer, while any common labourer can
keep in order and work these engines. If you prefer to send a person
with it, the cost will be about 40_s._ per week.
"I remain, Sir,
"Your most obedient servant,
"RICHARD TREVITHICK."
This letter indirectly points out two long-standing radical errors in
engineering phraseology. An early method of describing the value of
an engine was by stating the number of pounds it would lift one foot
high by the burning a bushel of coal, called the duty of an engine.
Trevithick's bushel was 84 lbs., while other engineers, under the same
term of bushel, meant various weights, up to 120 lbs.
Another form of speaking was the horse-power of an engine; meaning
that a horse could lift a certain number of pounds one foot high in
a minute, and that a steam-engine lifting ten times as much was a
10-horse engine; but, as Trevithick points out, a horse only works at
that rate for six hours out of twenty-four, while the steam-engine
works continuously, performing the work of forty horses, yet is called
a 10-horse engine.
The high-pressure engine suitable for the West Indies was to be adapted
to the existing horse or mule machinery, that either power might be
used. Its first cost and expense in working to be much less than that
of the Watt low-pressure steam vacuum engine.
[Rough draft.]
"SIR CHARLES HAWKINS, Bart.,
"CAMBORNE, _June 13th, 1812_.
"Sir,--Yours of the 15th of last month I received, enclosing a drawing
of a sugar-mill from Mr. Trecothick, which I should have answered per
return, but was at that time in treaty for an engine for a sugar-mill
with a Mr. Pickwood, who is in St. Kitts in the West Indies.
"The engine is now being erected at Hayle Foundry, of the power
of twelve mules at a time, or equal to forty-eight mules during
twenty-four hours.
"The cost is 210_l._ complete, with numerous duplicate parts.
"I hope she will be finished and sent off in a short time.
"I have now so fully proved the use of those engines, that I have
engaged to take this one back if it does not answer their purpose, and
to refund the whole sum if they return the engine to me in working
order within four years.
"This gentleman says, if this engine answers he shall have two more
for his own use, and four of his friends are waiting to see the result
before ordering their engines.
"The mules that will be turned out of use by Mr. Pickwood's engine
will sell for five times the sum the engine will cost him, exclusive
of the wear of mules, with their keep and drivers, besides the greater
dispatch and pleasantness of working a machine instead of forcing
animals in so hot a climate.
"If your friend wishes an engine of this power and on the same terms,
I can get two made and sent to London nearly in the same time as one.
Enclosed I send to you a rough sketch of the engine and mill. I am of
your opinion, that Sir John Sinclair has taken a useless journey by
calling on the Navy Board, for nothing experimental will ever be tried
or carried into effect except by individuals.
"If I could get an Act of Parliament for twenty-one years for only
one-tenth part of the saving which I could gain over animal power and
expense, I have no doubt but that I could get money to carry the plan
fully into effect for propelling ships, for travelling with weights on
roads, and doing almost every kind of agricultural labour.
"But a patent is but for fourteen years, and open to constant
infringement; for the inventor of general and useful machinery is
a target for every mechanic to shoot at, and unless protected or
encouraged by some better plan than a common patent, will have the
whole kingdom to contend with in law, and most likely receive ruin for
his reward, which has too often been the case.
"A plan of such magnitude as this promises to be of, I think ought to
be carried into effect by subscription, and as soon as accomplished,
the subscribers to be repaid, and the invention thrown open for the
use of the kingdom at large. I think about 1000_l._ or 1500_l._ would
test the designs.
"It is expected that Mr. Praed will spend some time in this
neighbourhood; I hope I shall be able to prove to you and to him the
great use of propelling barges by steam. I have a small engine now
at foundry, and would put it on board one of their barges for your
inspection. I am very much obliged for your continued favours, and beg
pardon for so often troubling you. I have so fully proved the great
advantages resulting from those portable engines, that I very much
wish the public to have the full use of them.
"I remain, Sir,
"Your most humble servant,
"RICHARD TREVITHICK."
A 12-mule-power engine for St. Kitts was being erected at Harvey's
foundry at Hayle; Trevithick making himself liable for the whole cost,
in case it should not answer the purpose. The mules thrown out of work
by the engine would sell for five times as much as the engine cost, to
say nothing of the saving in wear and tear of drivers and mules, and
the unpleasantness of driving a mule in hot weather as compared with a
machine.
If an Act of Parliament would give him one-tenth of the saving he
could effect during twenty-one years, a company might be formed for
carrying into full effect his plans for propelling ships, travelling
with weights on roads, and performing almost every kind of agricultural
labour, while a patent for fourteen years was open to constant
infringement, and the inventor of useful machinery was a target for
every mechanic to shoot at, had law suits with the kingdom at large,
and ultimate ruin, as a reward for his labours. Inventions of such
general application, when fairly established, should be thrown open
to the public, Government paying the inventors their expenses, and
reasonable reward for their time.
[Rough draft.]
"MR. PICKWOOD,
"CORNWALL, CAMBORNE, _17th June, 1812_.
"Sir,--Yours of the 17th April I received about twenty days since,
and from that time to the present have been in treaty with Messrs.
Plummer, Barham, and Co., for your engine. We have now closed for
an engine complete, of the power of twelve mules at a time, with
suitable duplicates, chains, &c., for 210_l._ I very much wish for
your engine to be set to work by your own workmen, to show the
planters the simplicity and easy management of the machine, and also
save the expense of an engineer, which will tend to promote their
use. The engine will be set to work before it is sent off, and every
possible care taken to execute it in the most perfect order. From the
experience I have had with common labourers keeping these engines
in order, since I wrote to you, I have no doubt you will get on
satisfactorily.
"I hope to get the engine ready in five or six weeks, but I fear there
will be loss of time in shipping it. You may rest assured that I will
spare no time or attention to promote the performance of this engine.
I am so far satisfied with the probability of its fully answering your
purpose that I voluntarily offered Messrs. Plummer, Barham, and Co.,
that if you return it to me for working repairs within four years, I
will refund the whole of the sum I am to receive for it. I will take
particular care to mark every part and send you a full description.
"Enclosed I send you a sketch of the engine attached to a sugar-mill.
Please write to me by return of the packet; it may be in time, before
the engine is shipped, to alter, or send you such things as I may not
be acquainted with. I shall be glad to know the number of yards your
mules travel in an hour when going at what you call a fair speed, in
the mill, and also what number of rounds you wish the centre roll to
make in an hour when worked by the engine.
"I remain, Sir,
"Your very humble servant,
"RD. TREVITHICK.
"R. W. PICKWOOD, Esq.,
"_St. Kitts, West Indies_."
These are not the remarks of an uncertain schemer; every sentence
having the impress of the ability and fixed intention of perfecting the
work, and the belief that the simplicity of the engine would enable a
common labourer to use it.
[Rough draft.]
"SIR CH. HAWKINS, Bart.,
"CAMBORNE, _5th July, 1812_.
"Sir,--If your friend Mr. Trecothick intends to have a sugar-mill
engine immediately finished and sent out with the one I am now making
for Mr. Pickwood, he ought not to lose any time in giving his orders.
I have made inquiry at Falmouth about sending out Mr. Pickwood's
engine for St. Kitts on board a packet, which would save much time,
but I fear it cannot be granted unless application is made by some
person of note to the Post Office in London. Mr. Banfield of Falmouth
told me that if application was made to send out a model as a trial,
he had no doubt but it would be granted.
"This experiment with the portable engine that will travel from one
plantation to another and work without condensing water, is certainly
of the greatest consequence to the planters, and as the whole weight
will not exceed 1-3/4 ton, I should hope that the Commissioners at
the Post Office will grant this request. I am sorry to trouble you
so often about my business, but I beg the favour of your goodness to
inform me through what channel I ought to make this application.
"I remain, Sir,
"Your most obedient humble servant,
"RD. TREVITHICK."
This experiment with the 1-3/4 ton portable engine to travel from one
plantation to another, needing no condensing water, was certainly of
the greatest consequence to the planters in the West Indies, and should
have been of equal importance to the people in England.
Judging from the weight and cost, as compared with agricultural
engines of the present day, Trevithick was nearer the mark then than
we are now; its working without condensing water the engineers of that
day believed to be impracticable, a fundamental error which greatly
retarded the use of the high-pressure steam-engine. The providing
sufficient condensing water was often a most serious item of cost, and
as water mains were not in use, a deep well was a necessary part of a
steam vacuum engine.
[Rough draft.]
"GENTLEMEN, "CORNWALL, CAMBORNE, _October 16th, 1812_.
"Yours of the 30th of September I found at my house on my return
yesterday from a journey. I am sorry to inform you that Mr. Pickwood's
engine is not ready. Near three months ago I set my smiths and
boiler-makers to work to complete an engine for Mr. Pickwood, which
parts were finished five or six weeks ago. The other parts of the
engine, which were to have been made of cast iron, were ordered and
commenced at a foundry in this county, belonging to Blewett, Harvey,
and Vivian, and would have been finished and the engine shipped long
since had not these partners in the iron foundry quarrelled with
each other, and the Lord Chancellor has laid an injunction and set
idle their foundry. I have since ordered the castings to be made at
a foundry at Bridgenorth, in Shropshire, belonging to Hazeldine,
Rastrick, and Co., who will complete the engine and send it to you in
about two months, at which time I intend to be in town to set it to
work before it is shipped for the West Indies.
"I remain, Gentlemen,
"Your very humble servant,
"RICHD. TREVITHICK.
"MESSRS. PLUMMER, BARHAM, AND CO.,
"_London_.
"P.S.--Immediately on my receiving your order to prepare an engine for
Mr. Pickwood I wrote to inform him that I had begun it, and enclosed
a drawing of the engine with the method of connecting the engine to
the cattle-mills, and requested he would remit to me his remarks on
it, which I received by the last packet, from which it appears for
the best that the engine is not in a forward state, because the parts
would not have been so suitable to the purpose as they will now be."
Fortune was against Trevithick. A difficulty between his brother-in-law
Harvey, and his old partner Vivian, with Blewett, retarded the
completion of the engine; and the castings so anxiously waited for were
ordered from Hazeldine and Rastrick. The wrought-iron work was made by
the old smiths in his neighbourhood, who had long been in the habit of
hammering his schemes into shape. This patchwork way of constructing
engines made success much more difficult.
Trevithick often laughed heartily at the following incident which
occurred during this quarrel at Harvey's works:--Blewett sent a
handsome silver teapot to Miss Betsy Harvey, who kept her brother's
house, called Foundry House. Trevithick was sitting with them when
the box was brought in and opened. Mr. Henry Harvey was indignant at
Mr. Blewett sending a bribe or make-peace to his sister, and threw
the silver teapot under the fire-place. Trevithick, however, quietly
picked it up, pointed out the dinge it had received, wrapped his pocket
handkerchief around it, and saying, if it causes bad feeling here it
will do for Jane, marched away home with the pot. The writer drank tea
from it recently, and also laughed at the dinge.
The following was written to Mr. Rastrick in December, 1812:[12]--
"I have been waiting your answer to my last, and especially that part
respecting the West India engine, as there is a large field there for
engines of this kind. I have received an order for a thrashing engine
for Lord de Dunstanville of Tehidy, and as I wish those thrashing
engines to be known through the country, I intend to take one of
the engines ordered for Padstow and send it to Tehidy; one of the
Padstow farmers can wait until you make another for him; therefore I
would thank you to send the first finished by ship from Bristol for
Portreath or Hayle. Send a drum with everything complete, of which
you are a better judge than I; probably about 3 feet in diameter
and 3-1/2 feet long will be sufficient. There must be a fly-wheel,
with a notch to carry the rope, and also a small notch wheel on the
drum-axle. I think 6-1/2 feet diameter for the fly and 9-1/2 inches
diameter for the small wheel, will give speed enough to the drum. Mind
to cast a lump or screw on a balance of about 1 cwt. on one side of
the wheel. There must be two stands on the boiler, and a crank-axle
or otherwise a crank-pin in the fly-wheel, whichever you please; with
a shaft 3 feet long with a carriage. The engine to stand in a room
under the turn-about, 7-1/2 feet high, 7 feet wide, and 17 feet
long. The fly-wheel will stand across the narrow way of the room. The
rope will go up through the floor and the drum be shifted by a screw,
horizontally on the barn floor, so as to tighten the rope. I shall put
down the top of the boiler level with the surface, with an arched way
to the fire and ash-pit underground to prevent the chance of fire,
which the farmers are very much afraid of.
[Footnote 12: See rough draft, Trevithick's letter, 7th December, 1812,
chap. xvii.]
"I send you a sketch showing how it is to stand. I do not bind you
to the size of the drum or wheels, only the room that the fly-wheel
works in is but 7 feet wide. Put the engine and drum for Lord de
Dunstanville out of hand neat and well, as it will be well paid for,
and make the stands, &c., in your own way."
This description of Lord Dedunstanville's thrashing machine illustrates
the drawing of that supplied to Sir Charles Hawkins.
[Rough draft.]
"MR. RASTRICK, "CAMBORNE, _January 26th, 1813_.
"Sir,--I have your favour of the 10th inst., in which you do not
state the time when you expect I shall have either of the engines
that you are executing. As so much time has elapsed since the orders
were given, the persons that ordered them are quite impotent. The
ploughing engine that I sent you a drawing for, after being tried for
that purpose, was to have been sent to Exeter for pumping water out
of the foundations of a new bridge; but as they intend to begin their
work at the bridge before the end of March, the engine must be there
before that time, or they will erect horse machines and not use the
engine. I have therefore been obliged to send the small boiler that
I had for that purpose to Hayle Foundry, and get the castings made
there for this engine to get it in time to prevent losing the order.
I have also been obliged to take the small portable engine from Wheal
Alfred Mine and have new apparatus fitted to it, to apply this engine
for Plymouth Breakwater. A small engine, from the same patterns as
Sir Charles Hawkins' thrashing engine, which I had at work in a mine,
I have been obliged to send to one of the farmers at Padstow for
thrashing, instead of one of those engines that I ordered from you. I
expect that the people who ordered the engine for the West Indies are
also tired of waiting. I have two other applications for engines for
the West Indies, and the Messrs. Fox will want a great many engines of
that size for the Plymouth Breakwater. They are to provide machinery,
with every other expense, and I am to have a certain proportion of
what I can save over what it now costs them to do it by manual labour.
I think I have made a very good bargain, for if the plan succeeds I
shall get a great deal of money, and if it fails I shall lose nothing.
They have engaged with the Government to deliver 3,000,000 tons, for
which they have a very good price, even if it was to be done by men's
labour. I hope I shall get the engine soon on the spot, and will then
let you know the result. As the boiler that was intended for the
ploughing engine is to be sent to Exeter, I wish you to finish that
engine with boiler, wheels, and everything complete for ploughing and
thrashing, as shown in the drawing, unless you can improve on it.
There is no doubt about the wheels turning around as you suppose,
for when that engine in Wales travelled on the tramroad, which was
very smooth, yet all the power of the engine could not slip around
the wheels when the engine was chained to a post for that particular
experiment.
"That new engine you saw near the seaside with me is now lifting forty
millions 1 foot high with 1 bushel of coal, which is very nearly
double the duty that is done by any other engine in the county. A few
days since I altered a 64-inch cylinder engine at Wheal Alfred to the
same plan, and I think she will do equally as much duty. I have a
notice to attend a mine meeting to erect a new engine equal in power
to a 63-inch cylinder single, which I hope to be able to send to you
for. I have also an appointment to meet some gentlemen at Swansea, to
erect two engines for them, one to lift water, the other coal, which
you will hear more about, I expect, soon. If I can spare a few days
when at Swansea, I will call to see you at Bridgenorth. I have not
seen Mr. Richard since you left, but will call on him in a few days
and do as you request. If you think the fly-wheel is not sufficiently
heavy for his engine, add half a ton more to the ring.
"If you cannot finish all these engines at the same time, I would
rather the smaller ones should be finished first and Mr. Richards'
stand a little, because if his engine was now ready he would not pull
down his thrashing machine until he had nearly thrashed all his corn,
and the machine now stands on the spot where the mill is to be erected.
"If I call on you from Swansea I think I shall be able to show you a
new idea, which I think will, if carried into practice, be of immense
value. Please to write to me and say particularly how you are getting
on, and when you are likely to finish the engines ordered.
"R. T."
Trevithick had sent a drawing of a _ploughing_ engine to Rastrick at
Bridgenorth, that the castings might be made, while he himself was
having the boiler and wrought-iron work constructed in Cornwall. The
engine had been ordered as a portable pumping engine, for removing
water from the foundation of a bridge at Exeter; but before sending it
to its destination, he had arranged to plough with it, as a means of
perfecting the plans and drawings for a more suitable ploughing engine
then in construction, to be fitted "with boiler, wheels, and everything
complete for ploughing and thrashing, as shown in the drawing." The
_friction of the wheels on the ground would be greater than the power
of the engine_; therefore they would not slip when the full power was
applied to draw a plough any more than the Welsh engine, the wheels of
which did not slip though resting on smooth iron.
One of his small engines, which had been at work in a mine, was sent
as a thrashing engine to Padstow. It is evident that, having given
a portion of his attention for a year or two to the question of
steam agriculture, he had so far progressed in 1813 as to construct
thrashing machines, portable agricultural engines, and steam-ploughs to
be moved by wheels as in locomotives; reaping, sowing, and other work,
was also in future to be the work of the steam-engine.
A drawing by Trevithick--having as usual neither name, date, nor
scale, nor writing of any kind, but the watermark in the paper is
1813--illustrates his ideas expressed to Sir Charles Sinclair in
1812:--"It is my opinion that every part of agriculture might be
performed by steam." The thrashing and grinding engines were at work,
and the tormenting harrowing engine was probably designed for bringing
under steam cultivation the extensive commons referred to. In those
days, before the practice of underground drainage, the surface of
cultivated land was thrown into furrows, or a series of small hills
and vales, the latter acting as the surface drain for carrying off the
water.
Suppose the first step in cultivating a common to be the breaking of
the soil, and throwing it into uniform lines of rise and fall that
facilitated drainage without inconveniencing the tillage, what better
machine could have been devised than Trevithick's? A combination of the
modern tormentor and harrow loosened the ground to the required depth,
which was then, by a revolving wheel with spades, thrown on one side,
resulting in uniform lines of ridges and hollows. The steam-shoveller
was removed, or the tormentor irons raised, when only the harrow was
required.
The absence of the ordinary shafts at the front end of the framing
indicates that the spade-tormentor was not to be drawn by horses, but
whether by a locomotive or by a fixed engine is not self-evident.
[Illustration: TREVITHICK'S STEAM SPADE-TORMENTOR, 1813.]
[Rough draft.]
"MR. KENDAL, "CAMBORNE, _January 26th, 1813._
"Sir,--I have yours of the 17th inst. The thrashing machine engine is
ready for you, and shall be sent up immediately. I wish you to get
about 100 fire bricks, 200 common bricks, 20 loads of stone, and 20
bushels of lime. The house will get finished while I am fixing the
engine. About 1500 or 1600 weight of iron for your engine has been
sent to the Blue Hills Mine, St. Agness. I wish you could send down
your cart to fetch it from there to Padstow. There is no part of
these castings but may be easily conveyed in a common butt or cart.
When you have the stone, brick, and lime ready, and a cart to send to
St. Agness for the castings, please to write me, and I will come to
Padstow at the same time with them, and finish the engine. The sooner
you get ready the better, as I expect to have an engagement in about
four weeks' time, that would prevent my coming to Padstow for some
time; therefore I wish to get your engine finished before that time.
Please to write me as early as possible, and let me know when you will
be ready for me, and what day I shall meet your cart at St. Agness for
the castings.
"Your obedient servant,
"RICHARD TREVITHICK."
Real inventors hesitate not to erect their own engines, lend a hand
in building the house, walk to the scene of action, or take a lift in
a cart; and by such steps was the gift of genius moulded to the wants
of daily life; while the modern engineer of eminence, living in large
cities, knows little of the minutiæ of his work, or even of the working
mechanics on whose skill the success of his ideas is dependent.
"In 1815, Mr. Kendal, the proctor of Padstow, sent for me to repair
his steam-engine. To prevent the old disputes in collecting his corn
tithes, he had at work one of Captain Trevithick's steam thrashing
machines. The small farmers sent their corn produce to him to be
thrashed; the grain was measured, the tenth taken out, the remainder
returned to the farmer. The three-way cock, which worked the engine,
was joined in its shell; on freeing it the engine continued to work
very well."[13]
[Footnote 13: Captain Samuel Grote's recollections, 1858.]
"In 1818 I put a new four-way cock to a thrashing engine that Captain
Trevithick had made for Mr. Kendal, of Padstow, who was the receiver
of tithe corn. The boiler was a tube of wrought iron, about 4 feet in
diameter and 6 feet long, standing on its end. The cylinder was fixed
in the top of the boiler; an upright from the top of the cylinder
supported the fly-wheel shaft; a connecting rod from the crank-pin in
the fly-wheel was fastened to a joint-pin in the piston. The cylinder
had no cover. The four-way cock was worked by an excentric on the
shaft, moving a lever, which was kept in contact with the excentric by
a spring."[14]
[Footnote 14: Recollections of Captain H. A. Artha, Penzance, 1868.]
"About 1824 I worked in Binner Downs Mine one of Captain Trevithick's
puffer whim-engines. The boiler was cylindrical, made of wrought iron.
It stood on its end, with the fire under it, and brick flues around
it. The cylinder was let down into the top of the boiler. A four-way
cock near the top of the cylinder turned the steam on and off. The
fly-wheel and its shaft were fixed just over the cylinder. A lever and
rod worked the four-way cock and feed-pole. The waste steam puffed
through a launder into the feed-cistern. The cylinder was about 12
inches in diameter, with a 3-feet stroke."[15]
[Footnote 15: Recollections of Henry Vivian, Harvey and Co.'s Works,
1869.]
Mr. Kendal's steam thrashing machine remained at work at least six
years, during which time the only apparent repair was the four-way
cock, worked by an excentric, which, if neglected, was apt to stick
fast in its shell.
One of the puffer-whims erected about this time was similar to the
thrashing engine for Padstow, differing from the earlier one made
for Sir C. Hawkins, in having a portable boiler so arranged that if
necessary it could be easily placed on wheels.
[Rough draft.]
"SIR, "CAMBORNE, _March 15th, 1813_.
"I have your favour of the 11th inst. respecting a steam-engine for
thrashing. I have made several, all of which answer the purpose
exceedingly well. They are made on a very simple construction so as
to be free from repairs, and are kept in order and worked by the farm
labourers, who never before saw a steam-engine. The first I made on
this plan was for Sir Christopher Hawkins, who resides at this time
in Argyll Street, Oxford Street, London. If you call on him, he, I
doubt not, would give you every information you require respecting its
performance. This was a fixed engine, because it was only required to
work on one farm. It has been at work nearly eighteen months, and has
not cost anything in repairs, nor any assistance but from the labourer
who puts in the corn; he only gives three or four minutes every hour
to put on a little coal. A few pails of water, put into the furnace in
the morning, is sufficient for a day's work. They have at different
times tried what duty the engine would perform with a given quantity
of coal, and found that two Cornish bushels, weighing 168 lbs., would
get up steam and thrash 1500 sheaves of wheat in about six hours.
"Before this engine was erected, they usually thrashed 500 sheaves,
with three heavy cart-horses for a day's work. I cannot say exactly
the measurement of the corn that it thrashed, but it was considerably
above 60 winchesters of wheat with 168 lbs. of coal; not a halfpenny
in coal for each winchester of wheat.
"The engines that I have since erected have performed the same duty.
"The horse machinery is thrown out of use, but the same drum is turned
by the engine.
"A fixed engine of this power I would deliver to you in London for 100
guineas; it would cost you about 15_l._ more to fix the furnace in
brickwork.
"A portable engine costs 160 guineas, but it would cost nothing in
erecting, as it will be sent with chimney and every thing complete on
its own wheels (the drum, &c., excepted), which you may convey with
one horse from farm to farm as easy as a common cart.
"If you have not sufficient work for it you can lend it to your
neighbours. The last engine I erected was about three weeks since, for
a farmer that kept four horses and two drivers. The parts of the horse
machine thrown out of use, together with the four horses, sold for
more money than he gave me for the engine, exclusive of 4_l._ per week
that it cost him in horse keep and drivers to thrash 3000 sheaves per
week.
"Now the engine performs more than double that work, and does not cost
above 10_s._ per week; and the labourer in the barn does double the
work he did before for the same money. If you wish the same engine to
have sufficient power to turn one pair of mill-stones, the cost will
be 220 guineas.
"R. TREVITHICK.
"MR. J. RAWLINGS, _Strood, Kent_."
"CAMBORNE, _28th August, 1813._
"MESSRS. HAZELDINE, RASTRICK, AND CO.,
"Gentlemen,--Lord Dedunstanville's engine thrashed yesterday 1500
sheaves in 90 minutes with 40 lbs. of coal.
"RD. TREVITHICK."
The first steam thrashing engine was worked by a labouring man for
eighteen months, without needing repair, or even attention beyond three
or four minutes each hour to put on a little coal.
Necessary stoppages for various purposes caused a day's work to be
no more than the engine could perform in half a day. No additional
feed-water was required during an ordinary day's work to thrash 1500
sheaves of wheat with 168 lbs. of coal, while on a special occasion
that quantity was thrashed in an hour and a half, consuming only 40
lbs. of coal. Three horses during three days were required to do the
same amount of work. A farmer sold his horses used in thrashing for
more money than his engine cost, which did twice as much work at a
reduced expenditure, and also saved the feed of the horses.
Such an engine could be delivered in London for 100 guineas, while
a portable engine on wheels with a differently constructed boiler,
requiring no mason work, would cost 160 guineas.
[Rough draft.]
"GENTLEMEN, "CORNWALL, CAMBORNE, _19th August, 1813_.
"I have your favour of the 9th August, respecting steam-engines for
St. Kitts. I fear it will not be possible to get an engine ready by
the 1st of November.
"As you say the gentleman that is about to take them out is a clever
man, and likely to promote the use of them, I will make immediate
inquiry, and, if possible, will get one ready, of which I will inform
you in a short time.
"I very much wish that every person who intends to employ a
steam-engine of mine would first examine the engine, and be satisfied
with the construction before giving an order, for which reason I
must request you to send your friend down to Messrs. Hazeldine and
Rastrick's foundry, Bridgenorth, Shropshire, where he may see the
portable steam-engine that was made for Mr. Pickwood, which the
founders will set to work for his inspection in half an hour after
his arrival. As this gentleman has a taste for machines, and wishes
to make himself fully acquainted with the principle and use of the
steam-engine, he will be much gratified with the sight of this curious
machine and with the information he will receive from the founders,
which will be essentially necessary to him before leaving England.
"I am extremely disappointed that this engine was not forwarded to Mr.
Pickwood, as I find from his letter that he has an exceedingly clever
and active mind, and is a very fit person to take the management of
introducing a machine into a new country.
"This engine is engaged by a Spanish gentleman, who is going to take
out nine of my engines with him to Lima, in South America, in about
six weeks.
"I remain, your obedient servant,
"RICHD. TREVITHICK.
"MESSRS. PLUMMER, BARHAM, AND CO.,
"_London_.
"N.B.--If your friend goes to Bridgenorth, let him show this letter to
the founders."
The engine, intended for the West Indies, so pleased Mr. Uville, that
he begged to have it made over to him for South America, where it
worked the machinery for rolling gold and silver in the Mint at Lima.
"About 1815, while erecting a high-pressure pole-engine at Legassack
for Mr. Trevithick, and doing some repairs to Mr. Kendal's thrashing
engine, a Creole, I think called Nash, brought a note from Captain
Trevithick, stating that the bearer was anxious to be taught to erect
and work the portable engines for Jamaica.
"Sir Rose Price, who had property in the West Indies, had sent him to
Mr. Trevithick for that purpose."[16]
[Footnote 16: Recollections of Captain H. A. Artha, Penzance, 1869.]
It is therefore probable that some of Trevithick's engines reached
Jamaica. Sir Rose Price was well known to Lord Dedunstanville and Sir
Charles Hawkins, and living near them, saw the engines at work and
their fitness for his property in Jamaica.
Lord Dedunstanville's engine of 1812 was sold as old iron to Messrs.
Harvey and Co. not long before 1843. Having remained for some time
on the old-scrap heap, it was in that year again worked to drive
machinery. Instead of the original rope-driver on the fly-wheel, a
chain was used, the links of which caught on projecting pins on the
driving wheel. In that form it continued to work until 1853, before
which it was frequently seen by the writer prior to its removal to
make room for a more powerful engine.
What greater proof could be given of the fitness of design of this
early engine, than its long life of forty years under such rough
treatment, and the facility with which it was applied to different
uses. Mr. Bickle, who, from recollection, had made a sketch of this
engine before the writer had found Trevithick's sketch, says that after
the engine had ceased to work, the boiler was turned to account in
heating tar in the ship-builder's yard.
"In 1854 I saw working in a shed at Carnsew, in the ship-*building
yard of Harvey and Co., of Hayle, an engine working a stamps for
pounding up the slag and furnace bottoms from the brass-casting
foundry.
"I was then the foreman hammerman in Harvey and Co.'s smiths' shop
and hammer-mill, and frequently noticed this old engine and inquired
about it. It had been brought from Lord Dedunstanville's, at Tehidy
Park, where it at one time worked a thrashing machine. The boiler
was of wrought iron, built in brickwork, and looked like a big
kitchen-boiler. A flattish cover was bolted on to the top of the
boiler, and the cylinder was let down into this top.
"The cylinder had no cover; it was about 8 or 10 inches in diameter
and 2 or 3 feet stroke. The piston was a very deep one, with a joint
for the connecting rod which went direct to the crank, which was
supported on two upright stands from the cover on the boiler. The
fly-wheel had a balance-weight for the down-stroke. A pitch-chain for
driving passed over the wheel, which had pins in it, or projections,
to catch into the square links of the driving chain; it was worked by
a four-way cock."[17]
[Footnote 17: Recollections of Banfield, foreman with Harvey and Co.,
Penzance, 1869.]
"About 1843, when we were building iron boats for the Rhine, the old
engine was put to work to drive the tools or machinery in the yard.
She was very useful to us and worked very well. She worked about ten
years, and was then thrown out to make room for a new and larger
engine for our saw-mills. The chain-wheel for driving was made here,
it did not belong to it originally."[18]
[Footnote 18: Recollections of Mr. Warren, master ship-builder, Harvey
and Co., 1869.]
"My father (then the foreman boiler-maker) about twenty-four years ago
took the old engine from the scrap heap, where it had been for many
years, and set it to work in the tool shop. My father said it had come
from Tehidy as old iron."[19]
[Footnote 19: Recollections of Mr. Burral, jun., master boiler-maker,
Harvey and Co., 1869.]
The use of the high-pressure steam agricultural engine was not confined
to Cornwall. Mr. H. Pape, still carrying on business in Hazeldine and
Rastrick's old engine manufactory at Bridgenorth, says:--
"My father worked as a smith under Mr. Rastrick. Mr. Hazeldine had the
foundry when Trevithick's engines were made, and have heard my father
speak of them. I have seen three of them at work in Bridgenorth;
one of them at Mr. Jasper's flour-mill, it drove four stones, and
continued in work up to 1837; one at Sing's tan-yard worked up to
1840; and one was on Mr. Jasper's farm at Stapleford for doing farm
work. Mr. Smith, now on the farm, worked it up to about 1858.
"The engines that worked in Bridgenorth had cast-iron cylinders for
the outer casing of the boiler, one cylinder for small engines,
three or four cylinders bolted together for the larger ones. The
fire-tube was wrought iron, the chimney stood up by the fire-door.
The cylinder was let down into the boiler; it worked with a four-way
cock. There was a piston-rod, cross-*head, two guide-rods on the
top of the cylinder, and two side rods to the crank and pin in 'the
fly-wheel.'"[20]
[Footnote 20: Recollections of Mr. William H. Pape, Bridgenorth, 13th
June, 1869.]
"My first husband had to do with the foundry; his father, Mr.
Hazeldine, was a partner with Mr. Davies and Co. in 1816. In 1817 the
partnership was broken up, and the foundry carried on by Hazeldine. I
used to have two or three drawers full of drawings and account-books
that were brought from the works. I kept them for many years, but now
the greater part of them have gone to light the fire; all the drawings
are gone."[21]
[Footnote 21: Recollections of Mrs. Marm, Bridgenorth, 12th June, 1869.]
The engines described by Mr. Pape are of the type made by Trevithick,
in Wales, about 1804, having a fire-place in the boiler, and similar in
form to the Welsh locomotive.
The drawings which served to light the fires certainly included
Trevithick's plans for the steam-locomotive, ploughing engine, the
screw-propeller, and many others of equal interest.
"DEAR SIR, "STABLEFORD, _March 26th, 1870_.
"My grandfather's name was John Jasper, Esq., of Stableford; he must
have been one, if not the first, user of a steam-engine for thrashing,
winnowing, and shaking the straw all at one operation; it may have
been erected eighty years ago, for an old servant of the family
just now dead, aged ninety, worked when a boy in the steam-mill at
Bridgenorth erected by my grandfather about the same time.
"The thrashing engine was a side-lever engine, worked with a three
side-way cock and tappet, a cylinder about 8-1/4 inches in diameter,
and a 3 feet 4 inch stroke, cast-iron crank-shaft, cross-head, and
guides. The boiler was placed underneath the engine, the fire under
it, with brick flues. The boiler was about 9 feet long and 4 feet
diameter.
"The old side rods made of wood are still here, and so was the
engine until about twelve years ago. I sent the cylinder, &c., to
Coalbrookdale.
"I am, Sir,
"Yours truly,
"THOMAS SMITH."
The Stableford agricultural engine was probably made in 1804. The
cylinder, of 8-1/4 inches in diameter, is precisely the size of that
in the Welsh locomotive, but the stroke was reduced from 4 feet 6
inches to 3 feet 4 inches, being very nearly the same as the Newcastle
locomotive. The cross-head, side rods, and boiler were very similar to
the Welsh stationary engines of that date. This engine remained in use
more than fifty years.
The engines specially referred to in this chapter fully prove, from
their length of service, the practical character of Trevithick's
inventions, and of his having persevered with his high-pressure
portables until their usefulness as locomotives and as agricultural
helps had been established; but the ploughing, though fully designed,
and probably put into practice, was not followed up to the same
approach to perfection, or the record of its progress has been lost.
Since the foregoing was written, the following has been received:--
"DEAR SIR, "TREWITHEN, PROBUS, _May 17th, 1872_.
"The engine you refer to is still occasionally used here; when first
erected there was a large quantity of corn thrashed by it, but of late
years it has not been much used except for chaffing, bruising, &c.
"I remain, dear Sir,
"Yours truly,
"WM. TRETHNOY.
"F. TREVITHICK, Esq."
Trevithick's Trewithen engine, which sixty years ago was more
manageable than horses going momentarily faster or slower at the will
of a common labourer,[22] remains in use unchanged.
[Footnote 22: See vol. ii., p. 38.]
His preparations for South America, and application of high steam in
the large Cornish pumping engines, interfered with the perfecting the
smaller agricultural work.