28o Literary and Philosophical Society. 



ingenious contrivance was adopted for uniting the recipro- 

 cating electric currents developed, so as to give them one 

 uniform direction. By this contrivance Mr. Sturgeon suc- 

 ceeded in producing all the effects due to ordinary voltaic 

 currents, by means of the action of magnets on rotating 

 coils of wire. In the same year the great industry of Mr. 

 Sturgeon was rewarded by two other important inventions. 

 The first of these was that of the electro-magnetic coil 

 machine, an instrument devised for the purpose of giving a 

 succession of electric shocks in medical treatment, and 

 which has been generally preferred by medical men to all 

 others intended for similar purposes. The other was an 

 electro-magnetic engine, for giving motion to machinery. 



* In 1838 Mr. Sturgeon noticed a highly interesting 

 electro-calorific phenomenon, produced by a powerful 

 battery of one hundred and sixty pairs, provided by Mr. 

 Gassiot and Mr. Mason. On breaking the battery circuit 

 it was observed that the disruptive discharge of electricity 

 made the positive wire red hot, while the negative remained 

 comparatively cool. Mr. Sturgeon applied this fact to 

 elucidate some important points in the theory of heat. 



' About this time also Mr. Sturgeon prepared a paper 

 for the British Association for the Advancement of Science 

 on the very important subject of marine lightning con- 

 ductors. His researches on this subject enabled him to 

 point out the danger likely to arise from the conductors 

 then proposed for use in the Royal Navy by Sir W. Snow 

 Harris, by which the lightning was sought to be conveyed 

 through the body of the ship. He propounded at the 

 same time a new system whereby this danger might be 

 obviated. 



'In 1843 Mr. Sturgeon published a memoir in the 



