60 Mr. W. Crookes on the Discovery of the Metal Thallium, 



The question now, therefore, is scarcely one of mere priority 

 in the discovery or the publication of a fact, but a question of 

 common honesty. It is not so much whether I knew thallium 

 to be a metal in May, but whether I stole that knowledge from 

 M. Lamy in June. 



The fact that M. Lamy dates his first publication of the 

 metallic nature of thallium as having been made on the 16th of 

 May, would be in itself a sufficient proof that this accusation is 

 unfounded, since I had publicly described thallium as a metal on 

 the 1st of May, before having heard of M. Lamy's existence, or 

 having the most remote suspicion that any one but myself was 

 working on the same subject. M. Lamy, however, not only 

 ignores this fact, but also asserts that the substance then exhi- 

 bited by me was not thallium. By what authority he does so is 

 not stated. If it be for the same reason that in his paper of the 

 16th of May he declared the substance which I regarded as 

 thallium to be nothing but sulphide, he makes the statement now, 

 as he made it then, upon very insufficient grounds. I am unable 

 to perceive why M. Lamy should assume that the powder exhi- 

 bited as thallium on the 1st of May, 1862, was obtained by pre- 

 cipitation with sulphuretted hydrogen, and not the powder pre- 

 cipitated by zinc, and actually so described on the label in 

 the case as well as in my first paper in 1861*. It is only 

 by means of this assumption that M. Lamy's assertion can 

 be of any value ; and that this assumption is totally gratuitous 

 and unfounded will, I trust, be apparent to any one who compares 

 the reactions of thallium described by me in this Journal in 

 April 1861, with the brief account written on my labels in the 

 Exhibition. 



But really this has little to do with the question at issue. It 

 is of no importance whether the body which I had ticketed 

 " thallium, a new metallic element," was in the state of powder 

 or lump, pure or impure, or, indeed, whether or not there was 

 any thallium at all in it. M. Lamy cannot deny that the label, 

 at all events, was there publicly exhibited from the 1st of May; 

 and that, I maintain, is ample publication of the fact that I knew 

 thallium to be a " metallic element" from my own independent 

 researches. 



Fortunately I am able to bring forward positive evidence that 

 long before May 1862 I knew thallium to be a metal, and had 

 obtained it in a melted metallic state, and by electrolysis so far 

 back as January 1862, even before M. Lamy had seen the green 

 band in the spectrum. 



"When it was first suggested that I should exhibit illustrations 

 of thallium, I prepared a set of labels for the purpose; and 

 * See note, p. 62. 



