1825.] 
the. town of Caernarvon in North Wales, 
has been found, by a correspondent in Nos. 
49 and 54 of the ‘‘ Annals of Philosophy,” 
to be-changed into perfect white, by the 
application of a strong or white heat, with- 
out the apparent loss, or chemical change, 
of any of its component parts—the visible 
change being supposed to be merely optical, 
owing to the different action of the sub- 
stances on light, from their different stages 
of aggregation, occasioned by the different 
degrees of heat to which they have been 
exposed. 
The White Precipitate of Mercury has 
lately, and rather unexpectedly, been found, 
by Mr. Hennel, to consist of 
Per-oxide of mercury ....... 80 
Muriate of ammonia.......-. 20 
Phil. Mag. No. 323. ] 100 
Titanium Metal may be extracted from 
the minerals which contain it, and com- 
pletely separated from its. combinations, 
by processes which M. Peschier has de- 
seribed in the Journ. de Phys.; a transla- 
tion of which appears in the Phil. Mag. 
No..323; but it is incapable of a. short 
abridgment here. 
Common Blue Indigo, according to re- 
cent experiments by Mr. Dalton, contains 
about 13 percent. more of oxygen than the 
green solution of indigo in lime-water ; and 
the weight of an atom of indigo is 55:5, 
nearly, in his scale of equivalent weights. 
Native Oil of Laurel, when pure, is 
colourless and transparent, volatile, and 
evaporates without residuum ; inflammable, 
and burns entirely away; yielding, except 
it be mixed with alcohol, a dense smoke. 
Its specific gravity hardly exceeds that of 
alcohol. If one part of this oil be mixed 
with two parts of sulphuric ether, they 
combine, and form, perhaps, the lightest 
liquid which is known. Neither acids or 
alkalies appear to act on this very curious 
natural product (the oil of laurel) ofa large 
tree, growing in Spanish Guiana, between 
the Oronooko and Panine Rivers. The 
Indians eagerly search for indications of 
yesicles, in the internal layers of tlie bark, 
which contain the oil, which they let out 
by the chop of an axe, and dexterously 
apply a calabash to catch it. Its taste is 
warm and pungent, and its odour aromatic, 
something like spirits of turpentine; and 
the wood affords the same smell, and is 
brown. Dr. Hancock, who writes this 
account, says, the tree yig{ding this oil is 
not the Laurus sassafras, but probably be- 
Jongs to one of the generg Ocotea, Persea, 
or Litsea. It has congigerable medicinal 
Virtues, in rheumatic awd other cases.— 
Phil. Mag: No. 323. 
Spirits from Potatoes are now extracted 
in coénpiderable quautities, in the foreign 
_ + distilberies, and one such work is established 
_ in London, using potatoes, chiefly imported 
Mowsury Mac. No. 411. 
Spirit of Philosophical Discovery. 
537 
from Ireland. Steamed potatoes are bro- 
ken down into a fine paste by stirring, 
while hot ; adding boiling water and a little 
potash and quick-lime, to dissolve the vege- 
table albumen, and complete the conversion 
of the mass into fluid starch—from which 
the spirit is drawn, and its peculiar flavour 
removed by chlorate of potash; when a 
very pure spirit results. 
The Essence of Beer, in a dry powder, is 
said, in various publications, to have been 
invented by a German quack, inconside- 
rately called a chemist ; who pretends that 
from a cheap vegetable, which is to be had: 
every where, his powder may be prepared— 
to which water only being, added, ale or 
beer, of any strength between the weakest 
small-beer and the strongest ale, may be 
instantly produced!—and for the whole- 
someress and agreeableness of which beve- 
rage, himself and his pufiers pledge them- 
selves. 
A Composition for preserving Iron from 
Rusting has long been used in the French 
Navy, applied to wrought and cast-iron 
water-tanks, as also to: preserve the iron 
hoops of casks, &c. Bricks, of good ‘qua- 
lity, and free from imbedded stones, or large 
grains of sand, are pounded and ground to, 
a very fine powder, and this is mixed with 
resin and olive-oil, into a very soft paste, 
which is spread or brushed over the clean, 
surfaces of iron intended to be preserved ;; 
and then the iron is heated suficiently par-- 
tially to liquefy and spread the composition, 
like a varnish, on all the surfaces of the 
iron. This varnish is found not liable to 
decomposition, or to scale off. 
Cathartic Physic for a Horse has lately 
been discovered, in the dried seeds of the 
plant Croton tiglium; or even the husks 
théreof will serve, after the oil has been 
expressed—in doses of twenty or thirty 
grains for a strong animal, and less for a 
weakly one. Aloes, alone or mixed with 
calomel, have hitherto been the usual 
purging medicine of the veterinary surgeon. 
Half a grain or a grain of these seeds is a 
dose for the human patient. 
Fused Charcoal.—At length a specimen 
of fused charcoal (supposed artificial dia- 
mond) has been examined. The specimen 
was obtained by Professor Macnevin of 
New York, by means of Hare’s deflagrator ; 
who sent it to Dr. Cooper, and by him it 
was submitted to the examination of Pro- 
fessor Vanuxem; who found it to consist 
only of a large and small globule connected 
by a thread; colour black, without lustre ; 
Opaque. When struck, it yielded without 
breaking, receiving a polish like iron; when 
filed away, it gave—as iron or soft steel 
would do. It was attracted by the mag- 
net; and, when hammered, was malleable, 
Nitric acid, when heated, acted violently 
upon it, and, ultimately, gave per-oxide of 
iron, and a little silica. The proportion was 
about 1] to 5. But Messrs, Silliman and 
32 “Tare 
