August 19,1871.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
153 
I)r. Carpenter read a paper on the “Thermo-Dyna¬ 
mics of the General Oceanic Circulation,” which gave 
rise to considerable discussion, in which Sir William 
Thomson, Professor Stokes, and Professor G. C. Foster 
took part. 
Section B.—Chemical Science. 
This section met under the presidency of Dr. An¬ 
drews, F.R.S., who, in his address, spoke of the difficulty 
of giving’ a historical review of the science, more parti¬ 
cularly in organic chemistry, where it was impossible to 
grapple with the large number of valuable works which 
even a few months produce. We give an abstract of 
some of the principal topics referred to. In commencing, 
he remarked that amidst the vicissitudes to which scien¬ 
tific theories are liable, it was scarcely to be expected 
that the discarded theory of phlogiston should be resusci¬ 
tated in our day, and connected with one of the most im¬ 
portant generalizations of modern science. The phlogistic 
theory, elaborated nearly two hundred years ago by 
Beecher and Stahl, was not, it now appears, wholly 
founded on error ; on the contrary, it was an imperfect 
anticipation of the great principle of energy, which 
plays so important a part in physical and chemical 
changes. The disciple of phlogiston, ignorant of the 
whole history of chemical combination, connected, it is 
true, his phlogiston with one only of the combining 
bodies, instead of recognizing that it is eliminated by 
the union of all. 
Dr. Andrews referred to a recent attempt to ignore the 
labours of Black and his contemporaries, and to attribute 
the foundation of modern chemistry to Lavoisier alone; 
and said that, through the kindness of Dr. Black’s repre¬ 
sentatives, he had been permitted to examine his corre¬ 
spondence, which has been carefully preserved, and had 
been so fortunate as to find in it three original letters 
from Lavoisier to Dr. Black. They were written in 
1789 and 1790, and they appear to comprise the whole of 
the correspondence on the part of Lavoisier which passed 
between those distinguished men. He would crave per¬ 
mission to have them printed as an appendix to his 
address. Lavoisier, it will be seen, addresses Black as 
one whom he was accustomed to regard as his master, 
and whose discoveries had produced important revolu¬ 
tions in science. It may indeed be said with truth that 
Lavoisier completed the foundation on which the grand 
structure of modern chemistry has since arisen; but 
Black, Priestley, Sclieele and Cavendish were before 
Lavoisier, and tlieir claims to a share in the great work 
are not inferior to those of the illustrious French 
chemist. 
Among the questions of general chemistry, few have 
of late attracted more attention than the relations which 
subsist between the chemical composition and refractive ! 
power of bodies for light. About twenty years ago 
Delfis remarked that the refractive indices of the com¬ 
pound ethers increase with the atomic weight, and that 
isomeric ethers have the same refractive indices. The 
later researches of Gladstone and of Landolt have, on 
the whole, confirmed these observations, and have shown : 
that the specific refractive power depends chiefly on the 
atomic composition of the body, and is little influenced | 
by the mode of grouping of the atoms. These inquiries j 
have gone further, and have led to the discovery of the | 
refraction equivalents of the atoms. By comparing the 
refractive power of compound bodies differing from one 
another by one or more atoms of the same element, Lan¬ 
dolt succeeded in obtaining numbers which express the 
refraction equivalents of carbon, hydrogen and oxygen, 
and corresponding numbers have been obtained for other 
elements by Gladstone and Haagen. The whole subject 
has been recently discussed and enriched with many new 
observations in an able memoir by Gladstone. As might 
be expected in so novel and recondite a subject, some 
anomalies occur which arc difficult to explain. Thus, 
hydrogen appears in different classes of compounds with 
at least two refraction equivalents, one three times as 
great as the other; and the refraction equivalents of the 
aromatic compounds and their derivations as given bv 
observation are, in general, higher than the calculated 
numbers. 
In a “Report on the Heat of Combination” which was 
made to this Association in 1849, the existence of a group 
of isothermal bases wa3 pointed out. “As some of the- 
bases,—potash, soda, baryta, strontia,—” it was remarked, 
“ form what we may perhaps designate an isothermal 
group, such bases will develope the same, or nearly the 
same heat, in combining with an acid, and no heat will 
be disengaged during their mutual displacements.” The 
latest experiments of Thomson have given a remarkable 
extension to this group of isothermal bases. He finds 
that the hydrates of lithium, thallium, calcium and 
magnesium produce, when all corrections are made, the 
same amount of heat on being neutralized by sulphuric 
acid as the four bases before mentioned. The hydrate 
of tetramethylammonium belongs to the same class of 
bases. Ethylamin, on the other hand, agrees with am¬ 
monia, which, as has long been known, gives out less 
heat in combining with the acids than potash or soda. 
An investigation of the amount of heat evolved in the 
combustion of coal of different kinds has been made by 
Scheurer-Kestner and Meusnier, accompanied by analyses 
of the coal. Coal rich in carbon and hydrogen disen¬ 
gages more heat in burning than coal in which those 
elements are partially replaced by oxygen. After de¬ 
ducting the cinders, the heat produced by the combustion 
of 1 gramme of coal varied from 8215 to 9622 units. 
Tyndall has given an account of his experiments on 
the action of a beam of strong light on certain vapours. 
He finds that there is a marked difference in the absorb¬ 
ing power of different vapour for the actinic rays. Thus, 
the nitrate of amyl in the state of vapour absorbs rapidly 
the rays of light competent to decompose it, while iodide 
of allyl in the same state allows them freely to pass. 
Morren has continued these experiments in the south of 
France, and, among other results, he finds that sul¬ 
phurous acid is decomposed by the solar beam. 
Roscoe has prosecuted the photo-chemical investiga¬ 
tions which Bunsen and he began some years ago. For 
altitudes above 10 degrees the relation between the 
sun’s altitude and the chemical intensity of light is re¬ 
presented by a straight line. Till the sun has reached 
an altitude of 20 degrees, the chemical action produced 
by diffused daylight exceeds that of the direct sun¬ 
light. The two actions are then balanced, and at higher 
elevations the direct sunlight is superior to the dif¬ 
fused light. The supposed inferiority of the chemical 
action of light under a tropical sun to its action in higher 
latitudes proves to be a mistake. According to Roscoe 
and Thorpe, the chemical intensity of light at Para 
under the equator, in the month of April, is more than 
three times greater than at Ivew in the month of 
August. 
Hunter has given a great extension to the earlier ex¬ 
periments of *Saussure on the absorptive power of char¬ 
coal for gases. Cocoa-nut charcoal, according to Hunter's 
experiments, exceeds all other varieties of wood charcoal 
in absorptive power, taking up at ordinary pressures 
170 volumes of ammonia and 69 of carbonic acid. Me- 
thylic alcohol is more largely absorbed than any other 
vapour at temperatures from 90° to 127°; but at 159° 
the absorption of ordinary alcohol exceeds it. Cocoa- 
nut charcoal absorbs 44 times its volume of the vapour 
of water at 127°. The absorptive power is increased by 
pressure. 
Last year two new processes for improving the manu- • 
facture of chlorine attracted the attention of the section ; 
one of these has already proved to be a success, and I 
am glad to be able to state that Mr. Deacon has recently 
overcome certain difficulties in his method, and has ob¬ 
tained a complete absorption of the chlorine. May wo 
hope to see oxygen prepared by a cheap and continuous 
process from atmospheric air 'i With baryta the pro- - 
