o<) Mr. J. W. Swan. On some Voltaic Combinations [May 24, 



It has long been known that the disease is most common in the 

 dirty, ill- drained, ill-ventilated dwellings of the poor, and, even in 

 records intended to prove the contagiousness of phthisis, there are 

 few, if any, of transmission of the disease in clean, well-lighted, 

 well-ventilated houses or hospitals, even those for consumption. 

 Long before Koch's discoveries, and before the disinfection of sputum 

 was practised as it is now, the conveyance of the disease, under 

 these conditions, was recognised by many to be one of the rarest 

 events. 



If the results that we have obtained with sputum are confirmed 

 by others, as we trust they will be, they will afford some explanation, 

 of these facts. 



So far as they extend at present, they show (1) that finely divided 

 tuberculous matter, such as pure cultures of the bacillus, or " tuber- 

 culous dust," in daylight, and in free currents of air, is rapidly de- 

 prived of virulence, (2) that even in the dark, although the action is 

 retarded, fresh air has still some disinfecting influence, and (3) that in 

 the absence of air, or in confined air, the bacillus retains its power 

 for long periods of time.* 



VI. " On some Voltaic Combinations with a Fused Electrolyte 

 and a Gaseous Depolariser." By J. W. SWAN, M.A. Com- 

 municated by LORD RAYLEIGH, Sec. R.S. Received Feb- 

 ruary 28, 1894. 



It is well known that fused salts behave in many respects like 

 electrolytes in solution, and that voltaic combinations analogous to 

 well-known voltaic cells may be formed with fused electrolytes. 



The experiments of Brownf have recently illustrated this subject 

 in relation to the Daniell type of cell. For various reasons it 

 appeared to the writer desirable to ascertain the behaviour of a cell 

 with fused electrolyte and a gaseous depolariser, and corresponding 

 in this last particular to the Upward cell. 



The following is chiefly a record of some of the experiments made 

 in connection with this research. 



A cell of this kind may be looked at from a theoretical point of 

 view as follows : A rod of metal, M (fig. 1), is immersed in a fused 

 chloride of the same metal, MCI, and a chemically inactive conductor, 

 C, is also immersed in the fused salt ; when M and C are connected 

 with an electrostatic volt-meter, the metallic chloride is immediately 



* A portion of the expenses of this research has been defrayed by a grant from 

 the British Medical Association. 



f ' Roy. Soc. Tr jc.,' vol. 52, pp. 7591 . 



