
852 Literary and Philsfaphical Intelligence, 
ed as they rifeto the furface. If this re- 
gular heat be feadily kept up for a fufti- 
cient time, the copal Sig {well, and 
gradually diffolve, excepting a very fmall 
refiduum; but if it be fuffered to flacken 
or be raifed higher, the folution ftops, and 
cannot be brought back to the diffolving 
ftate. The veflel fhould not be opened 
till fome time after it be cold, otherwife the 
contents will be thrown out of the gas 
with great vehemence. nh Sapna of tur- 
entine flould be of the beft quality, fuch 
as is fold at Apothecaries- Hall. This 
varnifh is of a deeprich colour when view- 
ed in the bottle, but gives no colour to the 
pictures on which it is laid.—Copal will 
alio diffolve in {pirit of wine, with the 
affiftance of camphor. Diffoive. haif an 
ounce of camphor ina pint of pure {pirit 
of wine; put it in a glafs, and add four 
ounces of copal, in fmall pieces; apply 
heat-with the fame precautions as in the 
laft folution, till the copal is dificlved. A 
part cf it, however, feparates as the liquor 
cools, but will ferve for another operation. 
This forms a very bright f{olution, and is 
an excellent varnifh for pictures ; ‘and 
where the varnifhed fubffance will admit 
of being moderately heated, the camphor 
as Ww ell as the fpirit will be driven off, and 
will leave the copal pure on the work, 
and probably quite colourlefs and tran{pa- 
rent. Copal will diffolve With the fame 
eafe in {pirit of turpentine, by the affift- 
ance of camphor,, but not in fo largea 
quantity. 
In the Menthly Magazine for Septem- 
ber laft, an account was given of fome in- 
terefting experiments by Gzytez, in Paris, 
on the combuftion of the diamond ; where- 
by it was proved to be a fubftance fimilar 
to charcoal, but\containing much more of 
the pure carbonic principle. This fact has 
been farther afcertained by the very fingular 
experiment of fubftituting diamond inttead 
of charcoal, in the converfion of a {mall 
portion of malleable iron into fteel_ For 
this purpofe, a very {mall crucible of the 
pureft foft or malleable iron was made 
cut of heads of nails, and fitted with 2 
itopper of the fame metal, clofely fitting. 
Into this a fmall diamond was put, the re- 
maining {pace around the diamond was filled 
up with filings of the fame iron, and the 
fiopper rammed in very clofe. ‘The whole 
was then inclofed in an earthen crucible, 
this lafi in a larger of the fame material, 
and the whole clofely luted, and expofed 
for about an hour in a very ftrong forge 
furnace. When ail was cold, the crucible 
ef iron was found melted down into a but- 
[ December, 
ton of caft feel. This, when broken, exhi- 
bited a oe: fe&tly {mooth, uniform frae~ 
ture, and not a veftige of the diamond 
remained. The fieel was exaétly fimilar 
to that known in England by the name of 
calt Reel. The inference from this curious 
xperiment is, that as diamond will per- 
form the office of charcoal, in converting 
iron into ftecl, its nature is the fame or 
very fimilar to that of charcoal. 
, Mr. DutTToON, the author of the Zife- 
rary Cenfus, has in the prefs -a didactic 
poem, in four cantos, intitled, Tae Pur- 
LOSOPHER OF Naxos: it will be pub- 
lifed early in the month of December. 
Mr. Parxi iNSON, of Hoxton-fquare, 
author of the Medical Admzniiions, has in 
the prefs, befides the chemical work we 
have already announced, a fmall popular 
medical work, The Villagers Friend, 
confhfting of obfervaticns, intended to pre- 
ferve the health, and promote the happi- 
nets, of the hufbandman and mechanic. 
“The refearches of Prouft into the nature 
of the falts of iron, has fuggefted an im- 
provement in the preparation of common, 
ink, by previoufly caicining to whitenefs 
the green vitrio] which is ufed as the bafis 
of ail writing-inks.” The following pro- 
portions wii] give an excellent black ink. 
—Gall nuts in powder, four ounces; green 
vitriol, calcined to whitenels, two oonce 
and a eles ; water, two pints. Thdéfe ma- 
terials mutt be left to infufe cold for 24 
hours, and then add ten drachms of gum 
Arabic. The ink fhould be preferved in 
a ftcne jar, flightly covered, fo as to keep 
out the duft. 
In the Profe Effays and Tranfaltions of 
the Highland Society, vol. i. is given a re- 
-ceipt for dettroying caterpillars on gooie- 
berry bufhes, which has. obtained a pre-_ 
mium from the Society, after due examia- 
tion. It is as follows: Take one Scotch 
pint (two quarts Englith) of tobacco li- 
quor, and mix with it one ounce of alum ; 
when this is diffolved, dip a brufh in the 
liquor, and as foon in the beginning of the 
feaion as you perceive the leaves’ of the 
bufhes to be eaten by the grub, or covered 
with its eggs, which is ¢ generally on the 
under fide, hold the leafup, and drawyyour 
hand gently over the hairs of the bruth, by 
which a {mall fhower of ‘drops of the liqhcr 
will fall on the leaf, and wherever they 
touch the egg it wales deitroyed, or if 
the worm fhould be hatched, it will perifh 
in a few minutes, and may be fhaken off 
without injuring the leaf.—The tobacco 
liquor here mentioned, is the fuperfluous 
moifture contained in the roll tobacco, 
which 

