Prof. Hare's Apparatus Jor Freezing Water. 377 



tion of acetate of lead : — the metal was revived on the negative 

 wire. 



Solution of sulphate of copper was also subjected to the 

 action of the current. Decomposition immediately took place, 

 and the negative wire became completely covered with copper. 



Water was also decomposed, the hydrogen and oxygen 

 being collected in separate tubes. 



The above experiments were made by changing the con- 

 nexions and reversing the current ; and the results were ex- 

 hibited with as much promptitude as they could have been by 

 the employment of a voltaic battery. 



Hard steel was also magnetized by being placed in a heli- 

 cal part of the circuit. The poles were reversed at pleasure 

 by changing the connexion. 



A soft iron horse-shoe was magnetized to as high a degree 

 as by a voltaic battery. 



I have also made a great variety of electro-magnetic rota- 

 tions, and some other rather novel motions, with electric cur- 

 rents by magnetic excitation, which I intend to publish as 

 soon as opportunity permits. 



By publishing the above in the forthcoming Number of 

 your valuable Magazine you will much oblige 



Your very obedient servant, 



Artillery Place, Woolwich, W. STURGEON. 



Oct. 15, 1834. 



P. S. I beg permission thus publicly to acknowledge the 

 obligations under which I am placed for the very handsome 

 manner with which Mr. Payne undertook to procure me the 

 use of the magnet, and for the very able assistance of Mr. 

 Maugham, Chemical Lecturer, whilst carrying on the expe- 

 riments* W. S. 



LIV. Apparatus for Freezing Water by the Aid of Sulphuric 

 Acid. By R. Hare, M.D., Professor of Chemistry in the 

 University of Pennsylvania* '. 



T^HE congelation of water by its own vaporization, acce- 

 * lerated by exposure to the absorbing power of sulphuric 

 acid, or other agents, in vacuo, has always been a difficult 

 experiment. A distinguished Professor complained to me 

 lately of want of success in his efforts to repeat it. In. No- 

 vember 1832, after having three times succeeded in freezing 

 water by the process in question, yet having failed before 

 my class, I was ed to give more than usual attention to the 

 * Communicated by the Author. 

 Third Series. Vol. 5. No. 29. Nov. 1834. 3 C 



