Molecular Constitution of Water. 487 



(see " A Kinetic Theory of Solids ") will be of the order 

 '000052 x 273 x 7 times the mean diameter of the I1 2 group, 

 but as the H atoms move four times as fast as the O atoms, 

 and there are 2 of them to 1 of of about the same 

 size, we may give the oxygen atoms an amplitude ^ of the 

 linear interspace allotted to each H 2 0. The velocity of the 

 atom is of the order 46,000 cm. per sec, and the diameter 

 of the H 2 group of the order 2 x 10~ 9 cm., so the required 

 frequency is of the order 46 X 9 X 10 18 -^-(2x2x7x52x 273),. 

 or 10 15 per sec. As the frequency for the most luminous 

 part of the solar spectrum is of the order 5 x 10 14 , we find 

 that our calculated destructive frequency of vibration for the 

 molecules of trihydrol must be about the same as that of 

 some part of the measured solar spectrum, iu which the 

 frequency ranges from less than 10 13 to about 10 15 per sec. 

 If resonance plays an important part in the melting of ice r 

 then ice ought to absorb powerfully radiation of the right 

 period, and to show anomalous dispersion in neighbouring 

 parts of the spectrum. In the visible spectrum, ice shows no 

 anomalous dispersion. The absorption spectrum of ice in the 

 infra-red and ultra-violet regions would be worth study. 



The laws of the dissociation of dihydrol (H 2 0) 2 into hydrol,. 

 H 2 0, could be worked out by an examination of the be- 

 haviour of the vapour of water at pressures and temperatures 

 up to and beyond the critical. It is probable that in ordinary 

 water there is a little dissociation of dihydrol into hydrol. 

 The question arises as to whether (H 2 0) 2 can be split into 

 positive and negative ions H 2 0, the difference between which 

 and the molecules of water-vapour would be the same as the 

 difference between the zinc ion and the atom of zinc- vapour. 

 The theory of electric conduction in aqueous solutions may 

 be considerably affected by the possible participation of 

 H 2 ions. 



The difference between the H 2 molecule and the H 2 

 ion could be expressed by saying that each negative H 2 

 ion contained two negative electrons, whereas the molecule 

 H 2 contains a negative and a positive electron that equili- 

 brate one another within the molecule. The formation of 

 (H 2 0) 2 consists then in two H 2 molecules exchanging 

 electrons, so that one has two negative and the other two 

 positive, which equilibrate as long as the (H 2 0) 2 lasts. In 

 (H 2 0) 3 each H 2 has a positive and a negative electron, but 

 these, instead of equilibrating one another within the group, 

 equilibrate with those of the other groups so as to hold the 

 (H 2 0) 3 together. 



Mendeleeff, Crompton, and S. IT. Pickering have shown by 



