962 REPORT—1885. 
view that Professor Lodge and others seem to hold regarding the possibility of 
settling the important question of pure contact vesws chemical action by appeal to 
experiment. I may also point out that according to my hypothesis it is possible 
that the metals may.exert a considerable attraction for each other, especially those 
having monatomic molecules: + many alloys are undoubtedly compounds ; possibly 
not a few are compounds of the ‘molecular aggregate ’ class.” 
To return now for but a few moments to the subject of chemical change and its: 
intimate connexion with electrical phenomena. One application I would make of 
the views here put forward would he to explain the superior activity of bodies in 
the nascent state, and in particular of nascent-hydrogen. Briefly stated, I believe 
it to consist in the fact that nascent hydrogen is hydrogen in circuit—hydrogen in 
electrical contact with the substance to be acted upon. The experiments of Faraday 
and of Grove afford the clearest evidence that in order to bring about action 
between hydrogen and oxygen at ordinary temperatures it is merely necessary to 
make them elements in a voltaic circuit. The difference in the effects produced by 
‘nascent hydrogen ’ from different sources is, I imagine, attributable to the varia- 
tions in E.M.F. which necessarily attend variations in the constituent elements of 
the circuit. 
It is not so easy, however, as yet to explain some of the changes which take 
place at high temperatures. Mr. Dixon’s experiments have proved that a mixture 
of carbonic oxide and oxygen is non-explosive, but that explosion takes place if 
water he present, the velocity of the explosive-wave depending upon the amount 
of water present. When the mixture of the two gases is ‘ sparked,’ change takes 
place, but only in the path of the discharge. Mr. Dixon considers ‘that the car- 
bonie oxide becomes oxidised at the expense of the water, the hydrogen set free 
then becoming reoxidised.’ M. Traube, who in a series of papers has called atten- 
tion to the importance of water in promoting oxidation, has suggested that the 
oxygen and carbonic oxide together act on the water, forming hydrogen peroxide 
and carbonic acid: CO+20H,+0,=CO(OH),+H,0,; and that the peroxide 
then reacts with carbonic oxide to form carbonic acid: CO+0O,H, =CO(OH),. 
The carbonic acid, of course, is resolved into carbon dioxide and water (‘ Berichte, 
1885, p. 1890). Traube actually shows that traces of hydrogen peroxide are 
formed during the combustion. It appears to me that the water may exercise the 
same kind of action as it (or rather dilute sulphuric acid) exercises in a Grove’s gas 
battery, and that its hydrogen does not become free in any ordinary sense, The produc- 
1 Assuming that the heat absorbed in raising the temperature of a solid is mainly 
expended in overcoming intermolecular attraction, the high ‘atomic heat’ of metals 
may be regarded as evidence that their molecules powerfully attract each other, and 
hence that their molecular composition is relatively simple; and on this view the 
‘atomic heat’ of carbon and of a number of other non-metals and of some metal- 
loids is low owing to the extent to which the ‘affinity’ of the atoms is, as it were, 
exhausted in the formation of their molecules. Comparison of the ‘molecular heats ’ 
of chlorides and similar compounds with those of the oxides lends much support to 
this view, as we have reason to believe that the chlorides—which have high ‘ molecu- 
lar heats’—are of relatively simple molecular composition, and that the oxides— 
which have low ‘ molecular heats "—are of relatively complex molecular composition. 
The great difference in the specific heat of ice and liquid water may perhaps be simi- 
larly explained on the assumption that ice consists of complex aggregates of H,O 
molecules, whereas liquid water consists of aggregates of much simpler composition. 
2 The study of alloys from this point of view will probably furnish interesting 
results. It is noteworthy that the contact difference of potential of brass is less 
than that of copper, and much less than that of zinc, with the same solution, in all 
the cases quoted by Ayrton and Perry ; thus— 
Zinc Copper Brass 
Alm, >. z : . —'536 volt. ? oT 4 . — 014 
Sea salt . 5 : . —565 4, ‘ . —'475 ‘ . —'435 
Sal ammoniac : ROOK, | 5 A . —'596 5 . —'348 
It is especially important to examine the copper-tin alloys, which vary in electrical 
conductivity in so remarkable a manner, 
