Nov. 4, 1869| 
MA LORE. 
year. It was in 1830 that he was appointed Professor of 
Chemistry at the Andersonian University, Glasgow ; and 
it is said that his mother, who was on her deathbed, lived 
to hear the glad tidings of his appointment. He was now 
more favourably circumstanced for experimental labours, 
and we find that the seven years spent at the Andersonian | 
University were years of great activity. 
In 1837 he was appointed Professor of Chemistry in | 
the London University, now called University College, 
London, and he occupied that chair with great distinc- 
tion till the year 1855, when he succeeded Sir John 
Herschel as Master of the Mint, which appointment 
may be considered an acknowledgment on the part of the 
Government of his scientific services and of his high 
character. 
His numerous discoveries have been much quoted. 
Some of their theoretical bearings claim a brief notice 
here. 
His investigation of the phosphates is remarkable in | 
many ways. It was known that solutions of phosphoric | 
acid in water vary in their pro- 
perties ; and chemists were sa- 
tished with giving a name to 
the changes without investigat- 
ing their nature. These solu- 
tions contained phosphoric acid 
and water, and were assumed to 
have like composition. They 
were accordingly called isomeric. 
Graham observed that they differ 
from one another in the pro- 
portion of water combined with 
the acid, and constitute in rea- 
lity different compounds. 
He knew that water combines 
with acids as other bases do, and 
he showed that the various com- 
pounds of phosphoric acid and 
water constitute distinct salts, 
each of which admits of its 
hydrogen being replaced by 
other metals without disturbance 
of what we should now call the 
type. Thus, to use our present 
notation, the three hydrates 
PO,H,, P,O,H,, POH, corre- 
spond to the following propor- 
tions of acid and water :— 
POn sk Ol—2PO.E. 
POl tt 2H.0 — PO, EH, 
POs HO) 2P0.H 
Graham observed that the hy- 
drate PO,H, is constituted like‘a 
salt, inasmuch as its hydrogen can be replaced atom 
for atom by other metals, like sodium, potassium, &c., 
forming such compounds as PO,NaH.,, PO,Na,H, &c. 
In order to appreciate duly the powers of mind of the 
author of this admirable research, we ought to compare 
his methods of reasoning with those generally prevalent | 
among contemporary chemists, and on the other hand 
with the methods of to-day. One would fancy that 
Graham had been acquainted with the modern doctrines 
of types and of polybasic acids, so clearly does he describe 
the chemical changes in matter-of-fact language, and so 
consistently does he classify the compounds by their 
analogies. At that early period we find Graham considering 
hydrogen, in various salts, as a basylous metal ; an idea 
which (in spite of its undeniable truth) some chemists of 
the present day have not fully realised. 
Amongst minor chemical researches may be mentioned 
a series of experiments on the slow oxidation of phosphorus 
by atmospheric air. He discovered that this process (and 
the faint light which accompanies it) is arrested by the 
Tuomas GRAHAM (from a recent Photograph) 
presence in the air of a trace of olefiant gas, ;45 of the 
volume of the air being sufficient for the purpose. Still 
smaller proportions of some other vapours were found 
capable of producing this same effect ; spirits of turpentine 
being particularly remarkable, as less than a quarter of a 
thousandth of its vapour with air was found sufficient to 
prevent the slow oxidation of phosphorus. 
On another occasion Graham investigated phosphuretted 
hydrogen, and made some remarkable observations 
concerning the conditions of the formation of the 
spontaneously inflammable gas. One of these deserves 
especial notice in connection with the action of olefiant 
gas, and in preventing the oxidation of phosphorus. He 
found that phosphuretted hydrogen is rendered sponta- 
neously inflammable by the admixture of a very small 
proportion of an oxide of nitrogen, probably nitrous acid. 
One of the most obscure classes of combinations are 
those which water forms with various salts. These bodies 
are characterised by the chief peculiarities which belong 
to definite chemical compounds ; but chemists are as yet 
unable to explain them. 
Water, so combined is called 
water of crystallisation, and is 
said to be physically, not che- 
mically, combined. A very con- 
venient way of getting rid of a 
difficulty, by passing it on to our 
neighbours. 
Graham examined the pro- 
portion of such water of crys- 
tallisation in a _ considerable 
number of salts, and he more- 
over examined the properties 
which it has when so combined. 
He found that some of the 
water in an important class of 
sulphates is held far more firmly 
than the remainder, and with 
force equal to that with which 
water is held in various chemical 
compounds. He showed that 
such firmly combined water can 
be replaced by salts in a definite 
chemical proportion. In fact, 
he got fairly hold of the subject 
by chemical methods, and laid 
the foundation for an explana- 
tion of it. 
He discovered and examined 
compounds of alcohol with salts, 
and derived from them valuable 
evidence of the analogy between 
alcohol and water. 
On a later occasion he made 
a series of important experiments upon the transformation 
of alcohol into ether and water, by the action of hydric 
sulphate. Liebig had endeavoured to explain the forma- 
tion of ether in this process, by representing it as due to 
the decomposition at a high temperature of a compound 
of ether previously formed at a lower temperature ; such 
decomposition being due to the increased tension of the 
vapour of ether at the higher temperature. or 
Graham justly argued that if the decomposition were 
due to the tension of ether vapour, it would not take 
place, and ether would not be formed, if the tension were 
not allowed to exert itself. He heated the materials in a 
closed tube, and proved that ether was formed, although 
the tension of its vapour was counteracted by the pressure 
thus obtained. 
The line of research which occupied most of his atten- 
tion, and in which his results were perhaps the most im- 
portant, was that of diffusion; and it would be difficult to 
over-estimate the importance to molecular chemistry of 
his measurements, of the relative velocities of these 
