1806.] - 
A Summary of Mr, Brawpe’s expe- 
riments'.on guaiacum was read to the 
' Royal Society, at one of ifs meetings in 
January: from which it appears, that in 
Too grains of that fubfance there were 
22$ of water and oil; of empyreuma- 
tic oi! about 30; carbon 30; lime 9; car- 
bonated hydiogen gas about 8. On the 
fame and on 2 fubfequent evening was read 
a letter from F. A. Knicur, Efq. to the 
Prefident, on the defcent of the roots, and 
the elongation of the germs of plants + in 
this the author has endeavoured to deter- 
mine whether thedefcent of the roots of 
plants was the effect of an inherent prin- 
ciple; or the confequence of mechanical 
gravitation; and he determines that gra- 
vitation is the fole caufe of tke defcent of 
roots and afcent of germs and that both 
diverge in all direStions, when under the 
influence of equa! preflure. 
Mr. Harcuetr has laid before the 
Royal Society a third communication on 
artificial tanning : he finds that all guins, 
refins, and balfams, yield this fubitance 
on being treated’ with nitric acid. They 
all yield at one operation a certain quan- 
tity of this matter; but if-the procefs be 
continued too long the produ& is de- 
ftroyed. : 
A fpear-head, found at Gringley Carrs 
Common, Nottingham, has been exhibit- 
ed before the Society of Antiquaries. It 
1s faid to be of Roman origin, and to 
have been made of Corinthian brafs. Mr. 
Lysons, on the fame evening, furnithed 
fome facts refpeéting the origin and hift 
tory of fugar: from thefe it appears that | 
the ancients had nothing but honey; and 
that till about the year 620 of the prefent 
ra fugar-cane was wholly unknown. 
The difcovery is afcribed to a Venetian, 
who called it honey-cane. It is only 
about zoo years fince refined fugar was 
introduced into Europe from China by the 
Portuguefe and Englifh. Dr. Gartu- 
SHORE has exhibited before this learned 
body a letter from Mary cde Medicis, 
Queen of France, to her daughter Henri. 
etta Maria, Queen of Charles the Firit. 
According to the cuitom of thofe times, 
it was fealed with two feals united by a 
narrow tape or ribbon. 
Mr. NrcHouson has invented a fecret 
lock of more than fix thonfand combina- 
tions: it poffeffts the fullowing requifites : 
1. That ‘certain parts of ‘the lock are 
variable in pofition through a great num- 
ber of combinations, only one of which 
will allow the lock to be opened or fliut. 
2. This laft combination is variable at 
the pleafure. ef ‘the pofleffor, 3. It is 
Literary and Philofophical Intelligence. 
16i « 
not poffible, after the lock is clofed and. 
the combination difturbed, for any one, 
not even the maker himfelf, to difcover by 
any examination what may be the proper 
fituation of the parts required to open it. 
4. Trials of this nature will not injure 
the work. 5. It requires no key; and, 
6. It is as eafily opened in the dark as 
in the light. This lock confiftts of four 
wheels, and by adding a filth, the com- 
binations would be increafed to nearly fixty 
thouland. : 
Mr. Ropert Harrur has made feme | 
expeviments which feem to prove that the 
{mut in wheat exifts in the feeds, and is 
greatly remedied by being fteeped in lime 
previoufly to its being fowed. 
From exper,ments made by M. Vau- 
QUEFLIN on gum Arabic and gum Adra- 
canth, it fhould feem that they contain 
1, Accalcareous fait, mo frequently 
acetatecf lime; 2. Sometimes a malate 
of lime; 43- Phofphate of Iime;. and, 
4. Tron, which is prebably united alfo 
with phofphoric acid. : 
The Galvanic Society at Paris have at- 
tempted, but without fuccefs, to follow 
M. Pacchiani in the decompofition of 
the muriatic acid. After a feries of ac- 
curate experiments, they deciared it as 
their upinion, that the Profeilor was de- 
ceived as tothe nature of the acid which 
it was announced that he obtained, and 
that it was probably produced by fome 
animal or vegetable fubftance employed in 
the apparatus: they add alfo that they do 
not think it poftible to effect any thing by 
the a¢tion of the Galvanic pile, out ade- 
compofition of the water uied m the ex- 
periment. 
M. Curaupeau has given two me- 
thods for purifying oil :—the firtt is, ‘* To 
one hundred parts of rape-oil one part of 
fulphuric acid is to be added, diluted with 
fix times its weight of water; the mix- 
ture fhould be ftrongly agitated, and as 
foon as this is completely finifhed, it is left 
till the oil becomes clear, and when it is 
perfecily clear the purification 1s effected.”” 
The ation of the fulphuric acid in this 
procefs confiits in depriving the oil of abl 
its humidity, though it is itfelf mixed 
with water, and in feparating fromit a 
fubftance, the prefence of which dimi- 
nifhes the energy of the combuttion of the 
oil, covers the wick with charcoal, and 
protuces much fmoke s on the abftragtion 
of thefe principles, which are foreign to 
the oil, depends its quality of giinga 
good light. ‘The fecond method is, ** ‘To 
one hundred. parts). of rape-feed. cil ten 
parts of water are to be put, to we ace 
een 
