42 Mr. G. Fuller on a Water-spray Influence-machine. 



the table, and would point to the soluble colloidal hydrates 

 of iron and aluminium being many multiples of Fe 2 H 6 6 , 

 or A1 2 H 6 6 , which would give a molecular weight of only 

 214 and 157 respectively. The molecular weights of ferric 

 and aluminic chlorides, as determined by RaouhVs method 

 (T being 47), are about 114 and 106 respectively. 



All our experiments, therefore, while affording additional 

 illustrations of the value of Raoult's method, confirm the 

 belief that the molecule of a colloidal substance is an aggre- 

 gate of a very great number of atoms*. 



VI. Water -spray Influence- Machine. 

 By George Fuller f- 



THIS machine is for obtaining directly from a fall of water 

 a supply of electricity of a high potential. It consists 

 of four similar parts arranged symmetrically round a cen- 

 tral vertical support, and each division has the following 

 members. 



A nozzle, A, in connexion 

 with a head of water by means 

 of a pipe, a. 



A ring? B, of brass or copper 

 wire placed vertically below A, 

 and through which the water 

 descends when the machine is 

 in action. ™- 



A vessel, C, placed below B 

 to receive the water that has 

 passed through the ring. 



A brass tube, E F, between 

 the ends of which the vessel C 

 can turn about a horizontal 

 axis. 



An insulating glass rod, D, 

 to the top of which the tube 

 E F is attached, and with the 

 lower end fixed in a part of the 

 frame of the machine, G. 



{ 





""1 



!l! 





— JT1 



j (i 

 i '1 



Hi 



* Since this paper was read we have found that Paterno and Nasini 

 have arrived at the same conclusion from experiments on albumen and 

 gelatine {Lincei, April 7, 1889, p. 476). 



t Communicated by the Physical Society : read May 25, 1889. 



