696 THE POPULAR SCIENCE MONTHLY. 



Annates de Chimie. This apparatus, according to Prof. Sillirnan, 

 was the earliest and most remarkable of Dr. Hare's original con- 

 tributions to science. It revealed to the chemical student a source 

 of artificial power far transcending anything he had ever known 

 before ; and this, though the facts on which it was based were 

 not unknown. 



Lavoisier had directed a jet of oxygen on charcoal and had 

 burned the elements of water together ; but even he, and in the 

 face of these experiments, had failed to comprehend the power of 

 this heating apparatus, and it was left for the acumen of Hare to 

 demonstrate it and make it practically applicable. The author of 

 the biography in the American Journal of Science says of it, " In 

 our view, Dr. Hare's merit as a scientific philosopher is more clearly 

 established upon this discovery than upon any other of the nu- 

 merous contributions he has made to science." Dr. Hare's original 

 experiments were repeated in 1802 and 1803 in the presence of Dr. 

 Priestley and Messrs. Sillirnan, Woodhouse, and others. In recog- 

 nition of the discovery, Dr. Hare received the Rumford medal 

 from the American Academy of Science at Boston. An attempt 

 was afterward made, in 1819, by Dr. Clarke, of Edinburgh, to rob 

 him of the credit of this discovery ; and though he showed that 

 the oxyhydrogen apparatus had been before the public several 

 years, no attention was paid to his protests. The calcium and 

 Drummond lights also furnish instances of most important appli- 

 cations of Dr. Hare's invention, in which no reference is made to 

 him. He himself led the way to these devices by constructing an 

 apparatus on a gigantic scale, with large vessels of wrought iron, 

 capable of sustaining the pressure of the Fairmount Water Works, 

 with which he was able to fuse at one operation nearly two pounds 

 of platinum, with a resultant production of metal greatly purified. 



He devoted much labor and skill to the construction of new 

 and improved forms of the voltaic pile ; " and it is easy to show," 

 Prof. Sillirnan says, " that owing to his zeal and skill in this de- 

 partment of physics American chemists were enabled to employ 

 with distinguished success, the intense powers of extended series 

 of voltaic couples long in advance of the general use of similar 

 contrivances in Europe." 



In 1816 Dr. Hare constructed an instrument called the calo- 

 rimeter, in which great extent of surface was obtained by combin- 

 ing many large plates of zinc and copper into one series, and 

 plunging the whole at once into a tank of dilute acid. Great 

 magnetic and heating effects were obtained with this instrument, 

 and it was many years before any other voltaic apparatus was con- 

 structed in which the movement of so great a volume of heat was 

 attained with so low a projectile or intensive force. By it large 

 rods of iron or platinum were ignited and fused with splendid ex- 



