2>lotices respecting New Books. 427 



incident, however trifling, if it relates to a great scientific disco- 

 very, merits the attention of the historian. As it accidentally oc- 

 curred to me, and to me alone, to witness the original experiment 

 by which Mr. Faraday first condensed chlorine gas into a liquid, 

 I shall here state the circumstances under which its liquefaction was 

 effected. 



" I had been invited to dine with Sir Humphry Davy, on Wed- 

 nesday the .5th of March 1823, for the purpose of meeting the 

 Rev. Uriah Tonkin, the heir of his early friend and benefactor of 

 that name. On quitting nij!^ house for that purpose, I perceived 

 that I had time to spare, and I accordingly called in my way at the 

 Royal Institution. Upon descending into the laboratory, I found 

 Mr. Faraday engaged in experiments on chlorine and its hydrate 

 in closed tubes. It appeared to me that the tube in which he was 

 operating upon this substance contained some oily matter, and 

 I rallied him upon the carelessness of employing soiled vessels. 

 Mr. Faraday, upon inspecting the tube, acknowledged the justness 

 of my remark, and expressed his surprise at the circumstance. In 

 consequence of which, he immediately proceeded to file off the 

 sealed end ; when, to our great astonishment, the contents suddenly 

 exploded, and the oily matter vanished! 



" Mr, Faraday was completely at a loss to explain the occur- 

 fence, and proceeded to repeat the experiment with a view to its 

 elucidation. I was unable, however, to remain and witness the result. 



" Upon mentioning the circumstance to Sir Humphry Davy after 

 dinner, he appeared much surprised ; and after a few moments 

 of apparent abstraction, he said, ' I shall inquire about this expe- 

 riment to-morrow.' 



" Early on the next morning, I received from Mr. Faraday the 

 following laconic note: 

 " ' Dear Sir, 



* The oil you noticed j-esterday turns out to be liquid chlorine. 

 ' Yours faithfully, ' M. Faraday.* 



" It is well known that, before the year 1810, the solid substance 

 obtained bj' exposing chlorine, as usually procured, to a low tem- 

 perature, was considered as the gas itself reduced into that form : 

 Sir Humphry Davy, however, corrected this error, and first showed 

 it to be a hydrate, the pure gas not being condensable even at a 

 temperature of —40° Fahrenheit. 



" Mr. Faraday had taken advantage of the cold season to pro- 

 cure crystals of this hydrate, and was proceeding in its analysis*, 

 when Sir Humphry Davy suggested to him the expediency of ob- 

 serving what would happen if it were heated in a close vessel ; but 

 this suggestion was made in consequence of the inspection of results 

 already obtained by Mr. I'araday, and which must have led him to 

 the experiment in cjuestion, had he never communicated with Sir 

 Humphry Davy upon the subject. This avowal is honestly due to 

 Mr. Faraday." 



• The results arc contained in a short jiapcr in tiie Quartcrlj' .lournal of 

 Science, vol. xv. 



3 I 2 After 



