* * * * *
_Microscopic Objects._
The most delicate test objects for microscopes are the lines on the
feathers of butterflies or moths' wings, of which there are many
gradations; some easily demonstrated, and others only to be seen with
the most powerful reflectors, and to the best advantage by the simple
and uncondensed light of the lamp. The hair of a mouse is a very good
test object: it is best seen by daylight; the most difficult parts of
which are longitudinal lines in the transparent part of the hair, which
require high powers. The hair of the bat and seal are also fine tests.
The lines on the scales of the diamond beetle, &c. are excellent opaque
proof objects. The feet of flies are likewise very interesting.
* * * * *
_New Lilac Dyes._
Dr. Macculloch has lately produced two fine lilac dyes from plants of
domestic growth, not hitherto applied to this purpose. One is from the
berry of the Portugal laurel, and the other the black currant. The
simplest process with alum is all that is required for either; and as
far as his trials go, the best tint is produced by the former fruit.
* * * * *
_Dirty Windows._
We have frequently remarked small radiant and arborescent
crystallizations on dirty windows in London, and have found them to
consist of _sulphate of ammonia_. This salt, or at least, sulphite of
ammonia (which becomes sulphate by exposure to air), is an abundant
product of the combustion of coal.
_Brande's Journal._
* * * * *
_Indigo._
This valuable plant, which gives rise to as great speculation in India,
as hops in England, is much injured by wet weather; although the
rapidity of the growth of plants during much rain, in the temperature of
the tropics, is extraordinary, yet a proportional deficiency in all that
characterizes the vegetable world necessarily follows. This we find to
be the case with all forced vegetables; and the mildness of the radish
of hastened growth, when contrasted with the highly pungent and almost
acrid flavour of the slowly and gradually advanced one, may be adduced
as explanatory of this observation. Hence, it is practically well known
to manufacturers, that the indigo plant, however fine and luxuriant, as
is the natural result of much rain, is very deficient _in produce_, and
a similar loss is experienced even if the plant, without the fall of too
much rain, has grown up under cloudy weather. Sunshine, much and
continued sunshine, is essentially necessary for the proper exercise of
those secretory organs by which this peculiar drug is formed and
perfected.
Indigo leaves produce two dyes--blue and yellow; but the refuse leaves,
when boiled for an hour and a half, will render the water yellow, tinged
with green. This water, kept boiling for two hours, (supplying the loss
by evaporation), will, when filtered, afford a precipitate, which, when
dried, will in colour be a dun-slate, and in quantity perhaps about
equal to the blue extract such leaves have produced. This observation,
as it can lead to no practical advantage, is made for the man of
science, rather than the man of business.--_Mr. C. Weston_--_in Brande's
Journal._
* * * * *
_Chain Bridge._
Mr. Disney has lately erected at his seat the Hyde, Ingatestone, Essex,
a suspension bridge of common chain, which is much cheaper than either
wood or brick. It is fifty feet long, and four feet wide. The whole cost
of material, and workmanship scarcely exceeded 30_l_. Upon a rough
estimate, a wooden bridge of the same span would have cost from 80_l_.
to 100_l_., and a high arch probably from 150_l_. to 200_l_. The piers
or posts supporting the chains are of oak, but should they in ten or
fifteen years decay, 10_l_. in money, and three days in time would set
it up again.--_Brande's Jour._
* * * * *
_Stone Roofs._
The Romans employed _pumice_ in building their arched incombustible
roofs. This porous material possessed the additional advantage, when
combined with good cement, of rendering the arched surface one united
petrifaction, opposing (in consequence of its firm union) little lateral
pressure, comparatively, against the sustaining walls.
Bonomi, the architect, suggests that the principal cause of the
destructiveness of fires in large buildings, is the want of arched
surfaces of incombustible materials. This has been disastrously
exemplified in the destruction of the choir of York Minster, where the
roof of the aisles, which are solidly arched with stone, suffered no
injury; while the choir-roof, although much more raised above the action
of the fire, has been entirely destroyed by it.
* * * * *
_Fossil Saurians._
Several beautiful specimens of fossil saurians, or animals of the lizard
tribe, have, as our scientific readers are aware, been found at Lyme, in
Dorsetshire; but the world would to this day have remained ignorant of
the treasures England possessed, but for the patient labours of three
female pioneers in this service, viz. _Mary Anning_, a dealer; _Miss
Congrieve_, and _Miss Philpots_, residents, who for years had been
collecting and preserving these bodies from the wreck of the coast; the
two last without any other view than the gratification of a laudable
curiosity, and who, with unequalled liberality, communicated their
collections to every man of science that visited the place; and it is to
liberal minds like theirs, and Miss Bennet's, of Wiltshire that we owe
the first rescuing of these natural gems from the spoilers. We copy this
from a communication of Mr. Cumberland to Brande's Journal, and are
truly pleased to record such amiable examples of female excellence in
scientific pursuits. At Dover, Portsmouth, and other places we could
name, we obtained the best information respecting the fossils of the
coast, from females resident there, and we need not add that this
circumstance imparted additional interest to our inquiries.
* * * * *
_The Zoological Society._
We copy the following from the Report to the Zoological Society, just
published:
"In the Museum in Bruton-street various improvements have taken place.
Additional cases have been erected, wherever space could be obtained,
for the exhibition of the different collections; and two persons have
been in constant employment in preparing and setting up the more
interesting specimens. An assistant has also been lately added, for the
arrangement of the shells, insects, and the other smaller subjects of
the collection; and much care has been bestowed upon the various
departments of comparative anatomy. An instructive as well as an
attractive series in every branch of zoology, but more particularly in
the groups of mammalia, birds, and insects, has thus been arranged for
inspection. A catalogue of the more important objects in the Museum has
been published; and a more detailed list, accompanied with scientific
notices of all the species, is in preparation.
"The increase in the number of subjects in the collection during the
last year has been considerable, and many of the additions have been of
the utmost importance to science. The whole of these, with a few
exceptions, have been presented by the friends of the society. A
detailed list of these donations which are too numerous for insertion in
this report, is laid upon the table; a reference to the contents of
which will evince that the spirit of liberality, which laid the
foundations of this already valuable collection, has not decreased.
"A very extensive correspondence has been established with naturalists
of foreign countries, and persons resident in distant parts, who are
anxious to promote the objects of the Society. Through these channels
many valuable acquisitions have been already received; and it is
expected that much of novelty and interest will continually pour in to
increase the attractions of the Museum and Menagerie.
"The Garden in the Regent's Park is the principal source of attraction
and of expense. The nature of the soil, which consists of a thick
ungrateful clay, increases the cost of every work. The health of the
animals requires that oak floors be raised above the surface of the
ground; and it is necessary to lay a thick substratum of dry material
under every inclosure and every walk. These disadvantages are however
amply counterbalanced by its immediate vicinity to the town. The Council
have, notwithstanding the nature of the soil, endeavoured to give to the
garden all the attractions which good cultivation and an abundance of
flowers can afford: and they have to return their thanks for the very
liberal supplies for this purpose which they have occasionally received
from the Horticultural Society. The resort to the garden has far
surpassed the most sanguine expectations of the Council; 112,226 persons
have visited it during the last year."
* * * * *