1825] 
ference in their hue. This chemical agency 
of light, on substances containing any, of 
the metallic oxides, appears to us worthy 
of more, investigation than it has hitherto 
‘received; as it might ‘ultimately lead to a 
discovery of the precise’ quantity and quali- 
ties of the metallic ingredients required in 
glass-making, so as to ensure the produc- 
tion of a pot of Blass’ of a certain quality, 
in all cases, instead of the process being, 
as at present, at most a matter of chance 
and uncertainty." . 
_ A, mode.of preyenting the scarlet fever, 
‘by means of inoculation, has been discover- 
ed in, Germany ; it is. said to be as certain in 
its Operation.as, vaccination in. preventing 
the small-pox. .As this disease can happen 
‘but once to the same person, the treatment 
“may probably_be efficacious. Ten or twelve 
grains.of extract, of Belladona are to be 
anixed with a pint, of water, and four spoon- 
fuls of this mixture are. to be. administered 
for ten successive . days; this produces 
red spots on the skin, like those of the 
‘searlet féver ; a contraction and burning in the 
‘throat, and a slight fever, in which are also 
symptoms of that disorder. Children who 
‘haye contracted this factitious disorder are, 
it is said, protected from the real one, and 
‘may, with impunity, sleep in the same bed 
‘with persons ill of the malady. Drs. Saem- 
‘mering, Hufeland, Meglin, &c. are parti- 
zans of the new system; and Dr. Lemerier 
‘of Paris has also adopted it. 
Method. of making Transparent Soap.— 
Tallow is the basis of all soaps for the 
toilette known under the name of Windsor 
soap; and tallow soap, dissolved by heated 
‘alcohol, becomes transparent, and returns to 
its solid state on cooling. It is this fact 
-which has led to the’ discovery of transpa- 
rent soap. When well prepared, this soap 
‘should have the appearance of white sugar- 
-eandy. It may also be coloured, and vege- 
table colours are preferable to mineral for 
this purpose. It may be made by putting 
a cake “of Windsor soap, cut small, into a 
thin glass “phial, filling the phial half full of 
alcohol, and’placing it near the fire till the 
soap be dissolved.” The mixture, put to cool 
in-a mould, gives the transparent soap. 
Moon's Eclipse.—Why is this body, when 
‘wholly eclipsed, sometimes entirely invisi- 
ble, and‘ at others considerably illumined 
with a sort of ruddy light? The cause usu- 
ally. ed is, the varying distance of the 
moor ‘the earth: but this solution is 
unsatisfact ry? for the eclipsed portion of 
‘the mooi has been seen very distinctly, 
both when she was near her apogee and her 
perigee. Perfia it will be found, that this 
variation’ depends ‘on the moon’s declina- 
tion, andl that ‘she ‘will always be visible 
when néar the’equator, and invisible when 
“nearthe: tropics) STS Pe Seek eee 
ss Exttabrdimary effects have “been attri- 
_ buted t6-tlie“inflnence of the mioon’s heat 
and light’; Wut these” are*yfuted—her heat 
Mon tHE MPAGANOM4 IGN OO 
Spirit of Philosophical Discovery. 
337 
not having been felt by the most seusible 
thermometer, and her light (which has long 
been regarded, when at full, in proportion 
“to the.sun’s, as 1:90,000) has, by a yaniety 
of observations, been determined to “be 
equally a forty-five thousandth part of the 
sun’s light. yO ‘om ma 
Natural History consists of an aggregate 
of information, derived, by observation,and 
experiment, from several .of the. .natural 
bodies which surround us; althoughy, at 
first, it was not and could not have been 
the intention to unite the yarious: results 
into a science. The observations made. at 
first, chiefly regarded the mode_ of, living, 
the age, the station, or place of abode .of 
animals and plants, but especially their 
usefulness, or obnoxiousness to man :.even 
minerals, which, at that early stage of in- 
formation, could scarcely possess any fur- 
ther interest, were taken into. considera~ 
tion, with respect to this latter. circum- 
stance. The mode by which the informa- 
tion, thus collected, could be communicated 
to others, was that of narration ; and as 
history is the word commonly used for de- 
signating whatever is comprized in a narra- 
tion, this aggregate of information received 
the name of JVatural History, or the His- 
tory of Natural Productions ; a name which 
was afterwards transferred to a science, alto- 
gether different from any thing that could 
properly be called history. a 
Natural history contains the: whole:com- 
pass of that information, which renders it 
possible to apply to natural bodies what is 
taught in other sciences. da Mapes 
Oil and Water.—Oils only enter into 
and fill up the interstices between the par- 
ticles or fibres of hydrhophic substances 
(i. e. such substances as have the faculty Of 
absorbing water, whether fluid or in ‘the 
state of vapour), without entering into’ the 
substance of the particles themselves ; and 
water, according to circumstances, not only 
enters these interstices, but penetrates; or 
combines with, the’ substance of thesé par 
ticles or fibres, and even at the time the ‘in- 
terstitial spaces are occupied by an oily 
fluid ; the présence of the oil not materi- 
ally influencing the absorption of ‘aqueous 
fluid, provided the surface of the solid’ body 
be not so coated with oil as-to.act the part 
of a varnish. Thus, we can explain how 
it is that human hair becomes so quickly 
affected by exposure on a damp evening, 
though oil may previously have been freely 
applied to it; whilé leather, which has: been 
soaked in oil, quickly and’easily absorbs and 
transmits moisture, when exposed ‘to‘its 
influence,—for example, in» walking over 
moist grass.—Janieson’s Ed: Phil. Journals 
Steam.—It appears from Mr.” Tréde 
gold’s excellent and valuable remarks “On 
Steam-Boats,”’ that to increase’ the Velocity 
of the same boat from seven ‘td ten Mies 
an hour, requires very neatly three” tines 
the power, and consequently, three "€ities 
Lem OK © Oo Searls Sotyek Fleosg dougie: 
