swim, having never seen much trial of them. Possibly they may be of
service in supporting the body while you are learning what is called
the stroke, or that manner of drawing in and striking out the hands
and feet that is necessary to produce progressive motion. But you
will be no swimmer till you can place some confidence in the power of
the water to support you; I would therefore advise the acquiring that
confidence in the first place; especially as I have known several
who, by a little of the practice necessary for that purpose, have
insensibly acquired the stroke, taught as it were by nature.
The practice I mean is this. Chusing a place where the water deepens
gradually, walk coolly into it till it is up to your breast, then
turn round, your face to the shore, and throw an egg into the water
between you and the shore. It will sink to the bottom, and be easily
seen there, as your water is clear. It must lie in water so deep
as that you cannot reach it to take it up but by diving for it. To
encourage yourself in order to do this, reflect that your progress
will be from deeper to shallower water, and that at any time you may,
by bringing your legs under you and standing on the bottom, raise
your head far above the water. Then plunge under it with your eyes
open, throwing yourself towards the egg, and endeavouring by the
action of your hands and feet against the water to get forward till
within reach of it. In this attempt you will find, that the water
buoys you up against your inclination; that it is not so easy a thing
to sink as you imagined; that you cannot but by active force get down
to the egg. Thus you feel the power of the water to support you, and
learn to confide in that power; while your endeavours to overcome it,
and to reach the egg, teach you the manner of acting on the water
with your feet and hands, which action is afterwards used in swimming
to support your head higher above water, or to go forward through it.
I would the more earnestly press you to the trial of this method,
because, though I think I satisfied you that your body is lighter
than water, and that you might float in it a long time with your
mouth free for breathing, if you would put yourself in a proper
posture, and would be still and forbear struggling; yet till you have
obtained this experimental confidence in the water, I cannot depend
on your having the necessary presence of mind to recollect that
posture and the directions I gave you relating to it. The surprize
may put all out of your mind. For though we value ourselves on being
reasonable knowing creatures, reason and knowledge seem on such
occasions to be of little use to us; and the brutes to whom we allow
scarce a glimmering of either, appear to have the advantage of us.
I will, however, take this opportunity of repeating, those
particulars to you, which I mentioned in our last conversation, as,
by perusing them at your leisure, you may possibly imprint them so in
your memory as on occasion to be of some use to you.
1. That though the legs, arms, and head, of a human body, being solid
parts, are specifically something heavier than fresh water, yet the
trunk, particularly the upper part, from its hollowness, is so much
lighter than water, as that the whole of the body taken together
is too light to sink wholly under water, but some part will remain
above, until the lungs become filled with water, which happens from
drawing water into them instead of air, when a person in the fright
attempts breathing while the mouth and nostrils are under water.
2. That the legs and arms are specifically lighter than salt water,
and will be supported by it, so that a human body would not sink
in salt-water, though the lungs were filled as above, but from the
greater specific gravity of the head.
3. That therefore a person throwing himself on his back in salt
water, and extending his arms, may easily lie so as to keep his mouth
and nostrils free for breathing; and by a small motion of his hands
may prevent turning, if he should perceive any tendency to it.
4. That in fresh water, if a man throws himself on his back, near
the surface, he cannot long continue in that situation but by proper
action of his hands on the water. If he uses no such action, the legs
and lower part of the body will gradually sink till he comes into an
upright position, in which he will continue suspended, the hollow of
the breast keeping the head uppermost.
5. But if, in this erect position, the head is kept upright above the
shoulders, as when we stand on the ground, the immersion will, by the
weight of that part of the head that is out of water, reach above the
mouth and nostrils, perhaps a little above the eyes, so that a man
cannot long remain suspended in water with his head in that position.
6. The body continuing suspended as before, and upright, if the head
be leaned quite back, so that the face looks upwards, all the back
part of the head being then under water, and its weight consequently
in a great measure supported by it, the face will remain above water
quite free for breathing, will rise an inch higher every inspiration,
and sink as much every expiration, but never so low as that the water
may come over the mouth.
7. If therefore a person unacquainted with swimming and falling
accidentally into the water, could have presence of mind sufficient
to avoid struggling and plunging, and to let the body take this
natural position, he might continue long safe from drowning till
perhaps help would come. For as to the cloaths, their additional
weight while immersed is very inconsiderable, the water supporting it
though, when he comes out of the water, he would find them very heavy
indeed.
But, as I said before, I would not advise you or any one to depend on
having this presence of mind on such an occasion, but learn fairly to
swim; as I wish all men were taught to do in their youth; they would,
on many occurrences, be the safer for having that skill, and on many
more the happier, as freer from painful apprehensions of danger,
to say nothing of the enjoyment in so delightful and wholesome an
exercise. Soldiers particularly should, methinks, all be taught to
swim; it might be of frequent use either in surprising an enemy, or
saving themselves. And if I had now boys to educate, I should prefer
those schools (other things being equal) where an opportunity was
afforded for acquiring so advantageous an art, which once learned is
never forgotten.
I am, Sir, &c.
B. FRANKLIN.
FOOTNOTE:
[36] Oliver Neale. _Editor._
ON THE SAME SUBJECT,
_In Answer to some Enquiries of M. Dubourg[37]._
**** I am apprehensive that I shall not be able to find leisure for
making all the disquisitions and experiments which would be desirable
on this subject. I must, therefore, content myself with a few remarks.
The specific gravity of some human bodies, in comparison to that
of water, has been examined by Mr. Robinson, in our Philosophical
Transactions, volume 50, page 30, for the year 1757. He asserts, that
fat persons with small bones float most easily upon the water.
The diving-bell is accurately described in our Transactions.
When I was a boy, I made two oval pallets, each about ten inches
long, and six broad, with a hole for the thumb, in order to retain it
fast in the palm of my hand. They much resembled a painter's pallets.
In swimming I pushed the edges of these forward, and I struck the
water with their flat surfaces as I drew them back. I remember I swam
faster by means of these pallets, but they fatigued my wrists. I
also fitted to the soles of my feet a kind of sandals; but I was not
satisfied with them, because I observed that the stroke is partly
given by the inside of the feet and the ancles, and not entirely with
the soles of the feet.
We have here waistcoats for swimming, which are made of double
sail-cloth, with small pieces of cork quilted in between them.
I know nothing of the _scaphandre_ of M. de la Chapelle.
I know by experience, that it is a great comfort to a swimmer, who
has a considerable distance to go, to turn himself sometimes on
his back, and to vary in other respects the means of procuring a
progressive motion.
When he is seized with the cramp in the leg, the method of driving it
away is to give to the parts affected a sudden, vigorous and violent
shock; which he may do in the air as he swims on his back.
During the great heats of summer there is no danger in bathing,
however warm we may be, in rivers which have been thoroughly warmed
by the sun. But to throw oneself into cold spring water, when the
body has been heated by exercise in the sun, is an imprudence which
may prove fatal. I once knew an instance of four young men, who,
having worked at harvest in the heat of the day, with a view of
refreshing themselves plunged into a spring of cold water: two died
upon the spot, a third the next morning, and the fourth recovered
with great difficulty. A copious draught of cold water, in similar
circumstances, is frequently attended with the same effect in North
America.
The exercise of swimming is one of the most healthy and agreeable in
the world. After having swam for an hour or two in the evening, one
sleeps coolly the whole night, even during the most ardent heat of
summer. Perhaps the pores being cleansed, the insensible perspiration
increases and occasions this coolness. It is certain that much
swimming is the means of stopping a diarrhœa, and even of producing a
constipation. With respect to those who do not know how to swim, or
who are affected with a diarrhœa at a season which does not permit
them to use that exercise, a warm bath, by cleansing and purifying
the skin, is found very salutary, and often effects a radical cure. I
speak from my own experience, frequently repeated, and that of others
to whom I have recommended this.
You will not be displeased if I conclude these hasty remarks by
informing you, that as the ordinary method of swimming is reduced
to the act of rowing with the arms and legs, and is consequently
a laborious and fatiguing operation when the space of water to be
crossed is considerable; there is a method in which a swimmer may
pass to great distances with much facility, by means of a sail. This
discovery I fortunately made by accident, and in the following manner.
When I was a boy I amused myself one day with flying a paper kite;
and approaching the bank of a pond, which was near a mile broad,
I tied the string to a stake, and the kite ascended to a very
considerable height above the pond, while I was swimming. In a little
time, being desirous of amusing myself with my kite, and enjoying at
the same time the pleasure of swimming, I returned; and loosing from
the stake the string with the little stick which was fastened to it,
went again into the water, where I found, that, lying on my back and
holding the stick in my hands, I was drawn along the surface of the
water in a very agreeable manner. Having then engaged another boy
to carry my clothes round the pond, to a place which I pointed out
to him on the other side, I began to cross the pond with my kite,
which carried me quite over without the least fatigue, and with
the greatest pleasure imaginable. I was only obliged occasionally
to halt a little in my course, and resist its progress, when it
appeared that, by following too quick, I lowered the kite too much;
by doing which occasionally I made it rise again. I have never since
that time practised this singular mode of swimming, though I think
it not impossible to cross in this manner from Dover to Calais. The
packet-boat, however, is still preferable. ****
B. FRANKLIN.
FOOTNOTE:
[37] This and the four following extracts of letters to M. Dubourg,
are re-translated from the French edition of Dr. Franklin's works.
_Editor._
TO M. DUBOURG.
_On the free Use of Air._
_London, July 28, 1760._
**** I greatly approve the epithet which you give, in your letter
of the 8th of June, to the new method of treating the small-pox,
which you call the _tonic_ or bracing method; I will take occasion,
from it, to mention a practice to which I have accustomed myself.
You know the cold bath has long been in vogue here as a tonic; but
the shock of the cold water has always appeared to me, generally
speaking, as too violent, and I have found it much more agreeable
to my constitution to bathe in another element, I mean cold air.
With this view I rise almost every morning, and sit in my chamber
without any clothes whatever, half an hour or an hour, according
to the season, either reading or writing. This practice is not in
the least painful, but, on the contrary, agreeable; and if I return
to bed afterwards, before I dress myself, as sometimes happens, I
make a supplement to my night's rest of one or two hours of the most
pleasing sleep that can be imagined. I find no ill consequences
whatever resulting from it, and that at least it does not injure my
health, if it does not in fact contribute much to its preservation. I
shall therefore call it for the future a _bracing_ or _tonic_ bath.
****
B. FRANKLIN.
_On the Causes of Colds._
_March 10, 1773._
**** I shall not attempt to explain why damp clothes occasion
colds, rather than wet ones, because I doubt the fact; I imagine
that neither the one nor the other contribute to this effect, and
that the causes of colds are totally independent of wet and even of
cold. I propose writing a short paper on this subject, the first
moment of leisure I have at my disposal. In the mean time I can
only say, that having some suspicions that the common notion, which
attributes to cold the property of stopping the pores and obstructing
perspiration, was ill founded, I engaged a young physician, who is
making some experiments with Sanctorius's balance, to estimate the
different proportions of his perspiration, when remaining one hour
quite naked, and another warmly clothed. He pursued the experiment
in this alternate manner for eight hours successively, and found his
perspiration almost double during those hours in which he was naked.
****
B. FRANKLIN.
_Dr. Stark_[38].
_May 4, 1773._
**** The young physician whom I mentioned is dead, and all the notes
which he had left of his curious experiments are by some accident
lost between our friends Sir John Pringle and Dr. Huck (Saunders);
but these gentlemen, if the papers cannot be recovered, it is to be
presumed, will repeat the experiments themselves ****
B. FRANKLIN.
_Dr. Lettsom._
_London, August 30, 1769._
**** This letter will be forwarded to you by Dr. Lettsom, a young
American physician of much merit, and one of the peaceable sect of
Quakers: you will therefore at least regard him as a curiosity, even
though you should have embraced all the opinions of the majority of
your countrymen concerning these people ****
B. FRANKLIN.
FROM DR. ----[39] OF BOSTON, TO BENJAMIN FRANKLIN, ESQ. OF
PHILADELPHIA.
_Respecting the Number of Deaths in Philadelphia by Inoculation._
_Boston, Aug. 3, 1752._
SIR,
This comes to you on account of Dr. Douglass: he desired me to write
to you for what you know of the number that died of the inoculation
in Philadelphia, telling me he designed to write something on the
small-pox shortly. We shall both be obliged to you for a word on this
affair.
The chief particulars of our visitation, you have in the public
prints. But the less degree of mortality than usual in the common way
of infection, seems chiefly owing to the purging method designed to
prevent the secondary fever; a method first begun and carried on in
this town, and with success beyond expectation. We lost one in eleven
one-sixth, but had we been experienced in this way, at the first
coming of the distemper, probably the proportion had been but one in
thirteen or fourteen. In the year 1730 we lost one in nine, which is
more favourable than ever before with us. The distemper pretty much
the same then as now, but some circumstances not so kind this time.
If there be any particulars which you want to know, please to signify
what they are, and I shall send them.
The number of our inhabitants decreases[40]. On a strict inquiry,
the overseers of the poor find but fourteen thousand one hundred and
ninety Whites, and one thousand five hundred and forty-four Blacks,
including those absent, on account of the small-pox, many of whom, it
is probable, will never return.
I pass this opportunity without any particulars of my old theme.
One thing, however, I must mention, which is, that perhaps my last
letters contained something that seemed to militate with your
doctrine of the _Origin_, &c. But my design was only to relate the
phenomena as they appeared to me. I have received so much light and
pleasure from your writings, as to prejudice me in favour of every
thing from your hand, and leave me only liberty to observe, and a
power of dissenting when some great probability might oblige me: and
if at any time that be the case, you will certainly hear of it.
I am, Sir, &c.
FOOTNOTES:
[38] The works of Dr. Stark, including the experiments alluded to,
have since been published. _Editor._
[39] Dr. Perkins. _Editor._
[40] Boston is an old town, and was formerly the seat of all the
trade of the country, that was carried on by sea. New towns, and
ports, have, of late, divided the trade with it, and diminished its
inhabitants, though the inhabitants of the country, in general, have
greatly increased.
FROM BENJAMIN FRANKLIN, ESQ. OF PHILADELPHIA.
_In Answer to the preceding._
_Philadelphia, Aug. 13, 1752._
SIR,
I received your favour of the 3d instant. Some time last winter I
procured from one of our physicians an account of the number of
persons inoculated during the five visitations of the small-pox we
have had in twenty-two years; which account I sent to Mr. W. V. of
your town, and have no copy. If I remember right, the number exceeded
eight hundred, and the deaths were but four. I suppose Mr. V. will
show you the account, if he ever received it. Those four were all
that our doctors allow to have died of the small-pox by inoculation,
though I think there were two more of the inoculated who died of the
distemper; but the eruptions appearing soon after the operation, it
is supposed they had taken the infection before, in the common way.
I shall be glad to see what Dr. Douglass may write on the subject. I
have a French piece printed at Paris, 1724, entitled, _Observations
sur la Saignée du Pied, et sur la Purgation au commencement de la
Petite Verole, & Raisons de doubte contre l' Inoculation._--A letter
of the doctor's is mentioned in it. If he or you have it not, and
desire to see it, I will send it.--Please to favour me with the
particulars of your purging method, to prevent the secondary fever.
I am indebted for your preceding letter, but business sometimes
obliges one to postpone philosophical amusements. Whatever I
have wrote of that kind, are really, as they are entitled, but
_Conjectures_ and _Suppositions_; which ought always to give place,
when careful observation militates against them. I own I have too
strong a penchant to the building of hypotheses; they indulge my
natural indolence: I wish I had more of your patience and accuracy in
making observations, on which, alone, true philosophy can be founded.
And, I assure you, nothing can be more obliging to me, than your kind
communication of those you make, however they may disagree with my
pre-conceived notions.
I am sorry to hear that the number of your inhabitants decreases. I
some time since, wrote a small paper of _Thoughts on the peopling of
Countries_[41], which, if I can find, I will send you, to obtain your
sentiments. The favourable opinion you express of my writings, may,
you see, occasion you more trouble than you expected from,
Sir, yours, &c.
B. FRANKLIN.
FOOTNOTE:
[41] This paper will be found in a subsequent part of the present
volume. _Editor._
TO BENJAMIN VAUGHAN, ESQ.
_On the Effects of Lead upon the human Constitution[42]._
_Philadelphia, July 31, 1786._
DEAR FRIEND,
I recollect that when I had last the pleasure of seeing you at
Southampton, now a twelvemonth since, we had some conversation on
the bad effects of lead taken inwardly; and that at your request I
promised to send you in writing a particular account of several facts
I then mentioned to you, of which you thought some good use might be
made. I now sit down to fulfil that promise.
The first thing I remember of this kind was a general discourse
in Boston when I was a boy, of a complaint from North Carolina
against New-England rum, that it poisoned their people, giving
them the dry-belly-ach, with a loss of the use of their limbs. The
distilleries being examined on the occasion, it was found, that
several of them used leaden still-heads and worms, and the physicians
were of opinion, that the mischief was occasioned by that use of
lead. The legislature of Massachussetts thereupon passed an act,
prohibiting, under severe penalties, the use of such still-heads and
worms hereafter.
In 1724, being in London, I went to work in the printing-house of Mr.
Palmer, Bartholomew-close, as a compositor. I there found a practice,
I had never seen before, of drying a case of types (which are wet in
distribution) by placing it sloping before the fire.
I found this had the additional advantage, when the types were not
only dried but heated, of being comfortable to the hands working over
them in cold weather. I therefore sometimes heated my case when the
types did not want drying. But an old workman observing it advised me
not to do so, telling me I might lose the use of my hands by it, as
two of our companions had nearly done, one of whom, that used to earn
his guinea a week, could not then make more than ten shillings, and
the other, who had the dangles, but seven and sixpence. This, with a
kind of obscure pain, that I had sometimes felt, as it were, in the
bones of my hand when working over the types made very hot, induced
me to omit the practice. But talking afterwards with Mr. James, a
letter-founder in the same Close, and asking him if his people, who
worked over the little furnaces of melted metal, were not subject to
that disorder; he made light of any danger from the effluvia, but
ascribed it to particles of the metal swallowed with their food by
slovenly workmen, who went to their meals after handling the metal,
without well washing their fingers, so that some of the metalline
particles were taken off by their bread and eaten with it. This
appeared to have some reason in it. But the pain I had experienced
made me still afraid of those effluvia.
Being in Derbyshire at some of the furnaces for smelting of lead
ore, I was told, that the smoke of those furnaces was pernicious to
the neighbouring grass and other vegetables; but I do not recollect
to have heard any thing of the effect of such vegetables eaten by
animals. It may be well to make the enquiry.
In America I have often observed, that on the roofs of our
shingled-houses, where moss is apt to grow in northern exposures,
if there be any thing on the roof painted with white lead, such as
balusters, or frames of dormant windows, &c. there is constantly a
streak on the shingles from such paint down to the eaves, on which
no moss will grow, but the wood remains constantly clean and free
from it. We seldom drink rain-water that fall on our houses; and
if we did, perhaps the small quantity of lead descending from such
paint might not be sufficient to produce any sensible ill-effect
on our bodies. But I have been told of a case in Europe, I forget
the place, where a whole family was afflicted with what we call
the dry-belly-ach, or _colica pictorum_, by drinking rain-water.
It was at a country-seat, which, being situated too high to have
the advantage of a well, was supplied with water from a tank, which
received the water from the leaded roofs. This had been drank several
years without mischief, but some young trees planted near the house
growing up above the roof, and shedding their leaves upon it, it
was supposed, that an acid in those leaves had corroded the lead
they covered, and furnished the water of that year with its baneful
particles and qualities.