1809. ] 
fion of light and heat ; and that in propor- 
tion as their number is greater or lefs, 
may be expected more or lefs abundant 
crops of corn. 
In a fecond paper on the fame fubjeéct, 
Dr. Herfchel propofes thermometrical ob- 
fervations, as a future criterion of a de- 
fective or copious emiffion of the folar 
rays. He fufpeéts that one half of the 
fun is lefs favourable to a copious emif- 
fion of rays than the other; and that its 
variable luftre may pofibly appear, to 
other folar fyfems, as irregular periodical 
ftars are feen by us. 
Mr. Jos. pe Menpdoza Rios has given 
a detailed account of an improved refled- 
jae circle, which be thinks will be found 
to be tree from the imperfections attach’ 
ing to other inftruments of the fame kind. 
MEDICINE. 
Mr. CHEvENIx propofes: the follow- 
ing preparation as a fubftitute for Dr. 
James's powder:—-* Diffolve together, 
or feparately, in the leaf poffible por- 
tion of muriatic acid, equal parts of the 
white oxide of antimony, and .of phof- 
phate of lime. Pour this folution gra- 
dually into diftilled water, previoufly al- 
kalized by a fufficient quantity of ammo- 
niac."* A white and abundant precipt- 
tate will take place, which, well wafhed 
and dried, is the fubftitute for James’s 
powder, and by feveral medical gentle- 
men, of high reputation it is confidered 
as a capital improvement on that medicine. 
Mr. Ware has given the cafe of a young 
gentleman who recovered his fight when 
feven years of age, after having been de- 
prived of it by cataraéts before he was a 
year old. The obfervations on the cafe 
are highly-important, and differ very ma- 
terially from thofe long fince made by Mr. — 
Chefelden in a fimilar cafe. Befides 
conclufions particularly adapted to the 
furgical praétitioner, Mr. Ware infers— 
x. Chat when children are born blind, in 
confequence of having cataraéts in their 
eyes, they are never fo totally deprived of 
fight as not to be able, faintly, to dif 
tinguifh celour:—2z. That immediately 
on the acquifition of fight, by the removal 
of catara¢ts, they are able to form fome 
judgment of the diftance, and even out- 
line, of thofe ftrongly defined objeéts, with 
the colour of which they were previoufly 
acquainted. 
In Mr. ASTLEY CooPER’s obfervations 
on the deftruétion of the membrana tympani, 
we find feveral inftances in which the deaf 
have been fuddenly and effectually reftored 
to the fenfe of hearing, by punéturing the 
piembrana tyinpani, an opexation which, 
Proceedings of ‘Learned Societies. 
487 
if properly performed, 1s attended with fo 
little pain, that a patient who has expe- 
rienced it in one ear exprefles no unwil- 
lingnefs in fubmitting to it in the other. 
‘© A prejudice (fays Mr. Cooper) has pre~ 
vailed,, that the ear is too delicate an 
organ to be operated upon, or, as it is 
commonly exprefled, tampered with; and 
thoufands have thus remained deaf for the 
reft of their lives, who might have been 
reftored to hearing, had proper affilt~ 
ance been early applied. But this preju- 
dice, it is hoped, will now be done away, 
fince it appears, that the part which has 
been thought moft eflential to hearing, 
may be injured, or broken, without a depri- 
vation of the fenfe of hearing ; and that, 
even when this membrane is entirely de- 
ftroyed, another is found to perform its 
functions, fo that the powers of the organ 
have ftill been, in a confiderable degree, 
preferved,”” 
EXPERIMENTAL PHILOSOPHY. 
Mr. Davy has difcovered, that an acs 
cumulation of GaLvaNnic influence, ex- 
aétly fimilar to the accumulation in the » 
common pile, may be produced by the 
arrangement of fingle metallic plates, 
with different ftrata of fluids. 
The moft powerful clafs of GaLVanic 
batteries con{truéted with fluids and fingle. 
metals, is formed, when metallic fub< 
ftances, oxidable in acids, and capable of 
acting on folutions of fulphurets, are con- 
nected, as plates with oxidating fluids 
and folutions of fulphuret of potath, in 
fuch manner that the oppofite fides of every 
plate may be undergoing different chemi- 
cal changes, the mode of alteration being 
regular. Plates of filver, copper, or lead, 
may be arranged with woollen cloths 
moiftened, fome in acids, and others in 
folution of fulphurets. 
Dr. WOLLAsTON, from a courfe of ex- 
periments thade by him on the chemical 
production and agency of eleétricity, Rates 
it as his opinion, that the power of clec« 
tricity and Galvanifm depends on the oxi- 
dation of the metal; and he infers, that 
the fimilarity in the means by which both 
electricity and Galvanifm ap. ear to be ex- 
cited, as well as the refemblance vifible 
in their effxts, fhew that they are both 
effentially the fame, and that all the dif- 
ferences difcoverable in the effects of the 
latter may be owing to its being lefs in- 
tenfe, but produced in much larger quan- 
tity. | ra eat 
In Dr. HULME’s continuation of experi- 
ments on the light, which is fpontancoufly 
emitted from various bodies, and on folar 
light, it appears, from the fr? feries, that 
objects, 
