Xlll 



properties and the same constitution, and is not a compound body, but 

 oxygen in an altered or alio tropic condition." 



This work was continued by Andrews and Tait, and the results were 

 published in the ' Philosophical Transactions ' under the title " On the 

 Volumetric Relations of Ozone and the Action cf the Electrical Dis- 

 charge on Oxygen and other Gases." The theory of the constitution 

 of ozone now universally held is clearly indicated in this paper, 

 although its apparent improbability deterred the authors from dis- 

 cussing it fully. 



But by far the most interesting and peculiar part of Dr. Andrews' 

 work is to be found in his investigations in the borderland between 

 Chemistry and Physics. There his special ability, his power of 

 arranging experiments, of devising pieces of apparatus suited to the 

 particular purpose at the moment in view, of detecting sources of 

 error and providing simple effective means of avoiding them, and of 

 doing all this himself with the least possible help from the instrument 

 maker, comes into remarkable prominence. The apparatus with 

 which most of his work was done was made with his own hands, and 

 when, for instance, he wanted a casting, he personally superintended 

 the minutest details. This directness of his work, and his habit of 

 working alone, made him somewhat intolerant of assistance, as ifc 

 made him independent of it. The only exception to the solitariness 

 of his scientific work, a very notable exception, is the investigation of 

 Ozone, carried out in conjunction with Professor Tait. His researches 

 on the heat developed in chemical actions, for one of which he received 

 in 1844 one of the Royal Medals, and for the other in 1850 one of the 

 prizes given by the French Academy of Sciences, and that on the 

 continuity of the liquid and gaseous states, partly contained in his 

 Bakerian Lectures, and partly communicated posthumously to the 

 Society, were done strictly alone. If this independence and individu- 

 ality limited the amount of work done by him, it has the compensating 

 advantage that we know that every analysis and every observation 

 published by him were actually made with his own hands and eyes, so 

 that a reader of his paper is as nearly as possible in as good a position to 

 judge as to the soundness of his conclusions as if he had performed 

 the experiments himself. In reading his papers we are transported 

 at once to the laboratory ; without wearisome repetition we have all 

 the details before us, and we can follow every step of his argument as 

 if we had been present at every experiment on which it was founded. 



The investigation into the heat given out during chemical action 

 was begun while he was still engaged in medical practice ; this work 

 at once established his position as a genuine scientific discoverer, and 

 introduced him to the chemists and physicists of Europe. 



But the work which will always be most closely connected with his 

 name is the great investigation into the relation of temperature, pres- 



