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and Hooke and Mayow had looked still further forward into futurity with prophetic 

 glances, which seem to have been soon lost and forgotten by the inattention or want of 

 candour of their successors. Hales had made many experiments on gases, but without 

 sufficiently distinguishing their different kinds or even being fully aware that fixed air 

 was essentially different from the common atmosphere. . . . Dr. Seip had suggested 

 that the gas which stagnated in some caverns near Pyimont was the cause of the brisk- 

 ness of the water. . . . Dr. Black in 1755 had explained the operation of this liquid 

 in rendering the earths and alkalies mild. ' Such was the state of pneumatic chemistry 

 when Mr. Cavendish began these experimental researches.' ' His paper (Experiments on 

 Air, Phil Trans. 1784, p. 119), contains an account of two of the greatest discoveries in 

 chemistry that have ever yet been made public — the composition of water and that of 

 nitric acid,' and in that of 1785 (p. 372), he showed that nearly the whole of the 

 irrespirable part of the atmosphere is convertible into nitric acid, when mixed with 

 oxygen and subjected to the operation of the electric spark." " The last words that he 

 uttered were characteristic of an unalterable love of method and subordination ; he had 

 ordered his servant to leave him, and not to return until a certain hour, intending to pass 

 his latest moments in the tranquillity of perfect solitude ; but the servant's impatience to 

 watch his master diligently having induced him to infringe the order, he was severely 

 reproved for his indiscretion, and took care not to repeat the offence until the scene was 

 finally closed." (The last quotation is from Works of Thomas Young, Vol. II., 1855.) 



We shall have occasion later on to refer to other work of this 

 eccentric nobleman that is of interest to the physiologist, viz., an 

 account of his Attempts to imitate the Effects of the Torpedo (1776). 

 Most of these extracts are taken from the Life of Cavendish (1851, 

 Cavendish Society) by one of the noblest of nature's noblemen, viz., 

 George Wilson M.D., then Lecturer on Chemistry, Edinburgh. 



Nitrogen was discovered in 1772 by Rutherford, who found that 

 the irrespirable part of air, when treated with lime, still leaves another 

 gas. This gas we now call nitrogen, although Rutherford did not give 

 it that name. Lavoisier ascertained its properties, and preferred to 

 call it " azote," because it did not support life. Now we know this 

 gas as nitrogen — so called from its connection with nitre. Azote, 

 however, forms an integral part of every proteid and proteid-like 

 body — of the "physical basis of life " itself. 



JOSEPH PRIESTLEY. 



1733-1804. 



BORN in 1733 at Fieldhouse, near Leeds, he died in the far-off 

 Northumberland Town in Pennsylvania, on the banks of 

 the Susquehannah, about 120 miles from Philadelphia. 

 Strange and eventful history. A tractarian on religious subjects ; 

 an assistant parson in a small meeting-house in Needham Market, 

 Suffolk — income £30 a year ; Unitarian minister in a meeting- 

 house in Nantwich in Cheshire (1758), where he kept a school, and 

 taught privately, writing at this time his grammar and more tracts. 



