18246] ©; 
The first occultation of the. Herschel 
planet by the Moon will take place on 
the 6th of August. This interesting 
plienomenon never yet having oceur- 
red since the memorabie discovery of 
this planet, in March 1781. This 
occultation: will) also have the rare 
advantage of occurring within a very 
few minutes after the moon has passed 
the meridian-of London, and whilstyet 
she remains within the field of view of 
a transit telescope. The planet will 
enter the western or dark limb of the 
mneon at about half-way between the 
moon’s oulerand-the upper or northern 
part of her disc. ; 
Vhe gelatine of bones is prepared by 
M. Darcer at Paris, by submitting 
them for some hours to ebullition to 
remove the fat, after which they are 
treated with dilate muriatic acid, 
which dissolves all the phosphates of 
lime and magnesia, ‘and the carbonate 
ef lime, and leaves the pnre gelatine, 
preserving the forms and almost ithe 
sizes of the bones which have been 
operated upon in a flexible. state. 
These masses of gelatine are then 
exposed for a considerable period toa 
stream of clear cold water, to remove 
any -adhering acid or fat, and to give 
the requisite whiteness and .transpa- 
rency; which operations are repeated, 
if necessary; and at length the gelatine 
is dried in open baskets or nets, in an 
airy place, and then it is packed in 
bags or casks, and may be so kept, in 
a dry place, through almost any length 
of time. «In order to purify and fit 
this “bone-gelatine for food, it is cut in 
ieces and soaked in eold water, of 
which ‘in five or six hours it absorbs 
fifty-eight per cent. of its weight; two 
and a half parts of soaked gelatine are 
dissolved in a hundred parts of boiling 
Water, whereby a jelly is‘obtained for 
immediate ‘use, on cooling, without 
prolonging the boiling; otherwise, by 
continuing the boiling, the jelly is made 
thick enough to be cut out into thin 
cakes, which, when ‘dried as above 
Mentioned, will keep good any length 
of time in astore of provisions: the 
‘gelatine so prepared being equally 
imputrescible as it was originally in 
the bones. Glue prepared for joiners’ 
‘uses from this gelatine is foand one- 
half stronger in its adhesive qualities 
‘than the best Paris glue, from theskins 
‘and sinews of animals. It forms for 
‘the manufacturer of painted papers, 
: 
hs 
Spivit of Philosophical Discovery. 
being extinguished. 
wt 
and in distemper, a perfectly colour- 
less tremulous size, greatly preferable 
and less expensive than what was pre- 
viously used. Hats prepared withethis 
bone-glue, are less lable to cockie and 
blister, from the eficct of rain, than if 
prepared with the best Flanders glue. 
Lip-glue, for joining papers of the first 
quaitity, is prepared from this gelatine, 
and thin sheets of factitious horn, very, 
transparent and durable; and, by roll- 
ing or laminating it, M. Dareet pro- 
poses to prepare a kind of parchment, 
applicable to many uses.—Aunales de 
UIndustrie. 
Evaporation modified by Pressure.— 
M. €aGniakp de xa ‘Tour has. ascer- 
tained, by experiments which are 
recorded in the “‘ Annales de Chimie,” 
that alcohol of specific gravity °837, is 
capable by the application of heat of 
about 405° of Fam. of being wholly 
converted into vapour, in a space less 
than thrice its original buik, and that 
the elastic force of such vapouris about 
119 atmospheres. Also, that sutphurie 
ether is capable, by the application of 
320° of Farn. of being wholly converted 
into vapour, in a space less than twice 
iis original bulk; its elastic force 
balancing at the time about 374 
atmospheres: and water, at a tempe- 
yature near to that of melting zine, or 
705° Farn. becomes wholly vapour, in 
a space nearly equal to four times its 
former bulk. 
Vhe astonishing heat of the flume of 
oxy-hydrous gas, issuing from the com- 
pound blow-pipe, (originally invented 
by Dr. Hare, and published in 1802,) 
is such, that Mr. Thomas Skidmore 
found, on projecting this flame against 
the outside of a smail tinned iron eup, 
full of cold water, that the outside of 
the cup became red hot, and at length 
assumed a white heat, not only on its 
outside, but within, in contact with the 
water; and in an instant afterwards 
the flame broke through the side of the 
cup, and entered the water, without 
This suggested 
to him the plunging of the jet-pipe 
and flame. under water; which, alter 
due precautions, was eflected, and the 
flame continued to burn, with undimi- 
nished ‘energy, in actaal contact with 
the water: which latter, in a tumbler 
holding about half a_ pint, quickly 
became heated from about 56° to 1709 
of Farnh.—Silliman’s Journal, No. \2. 
BRITISH 
