pROCEEcmas of the polttecttnic association. 531 



'ened as much as the same paper would have been if exposed to the 

 sun's rays for one minute. 



Tlie production of these remarkable effects from electricity first 

 generated in six magnets weighing only one pound each, is not 

 •obtained without a corresponding expenditure of mechanical force, 

 for it was found the laro-e electro-ma2:net could be excited to such 

 a degree that the strong leather belt was scarcely able to drive the 

 machine. 



The author by these experiments shows the remarkable analogy 

 between the operation of the static forces of magnetism and of 

 cohesion in modifying dynamical phenomena, which throws addi- 

 tional light on the nature of magnetic force. The author concludes 

 from his varied experiments that magnetism is a mode of the force 

 ■of cohesion, or is, if the term be allowed, polar cohesion acting at 

 «ensible distances, the equivalent of magnetic force being obtained 

 at an expense of an equivale^nt of ordinary cohesive force (in an 

 •axial direction), so long as the iron continues 'to be magnetised. 



Production of Fricteonal Ei.ectricity in Increased Quantities. 

 Mr. Holz has, b}'- means of the Franklin electric machine, mani- 

 fested the same principle, illustrated by Mr. Wilde. A varnished 

 glass plate is revolved very near another plate having two or more 

 .pieces of cord attached which arc electrified by a piece of rabbed, 

 glass or ebonite, at the same instant a resistance is felt by the per- 

 son turning the handle of the machine, and this electrization of 

 the cord converts into a continuous stream of intense electricity 

 the force expended by the operation. 



Disinfectants. 



The discussion on the selected subject was opened by Dr. L. 

 Feuchtwanger, who gave an interesting account of various methods 

 for disinfection, several of which he had himself used. In conclu- 

 sion, he read extracts from a very able paper on this subject, which 

 appeared in the North British Review for June, 1865. 



Dr. L. Bradley presented the following paper on 



Disinfectants, Malaria and Malarious Diseases. 



So far as disinfectants can be made available in the promotion 

 of health, it is of the first importance that we understand them 

 and know how to use them. 



The etiology of malarious and pestilential disease is a topic of 

 the greatest moment, which, in proportion to its importance, has 



