EXPERIMENTS. 93 



elongating, and yielding when blown upon, and when the 

 hand or any other solid body was passed through them. 

 The whole appearance was described as being exceedingly 

 beautiful. 



This experiment was repeated with many different observ- 

 ers, from all of whom the same general description was ob- 

 tained the accuracy of which was further tested by varying 

 the experiments without the knowledge of the observers, and 

 noting the corresponding and uniform variations of the ap-. 

 pearances described. 



But, in order to obtain still further assurance that those 

 luminous appearances described by others were real, though 

 invisible to himself, the experimenter, by the aid of another 

 scientific gentleman, instituted the following additional test : 

 A very sensitive daguerreotype plate was prepared and placed 

 opposite to a large open magnet, in a closed box, enveloped 

 in thick bed-clothes, so that not a particle of ordinary light 

 could enter it. After the lapse of sixty-four hours, the plate, 

 when exposed to mercurial vapor, was found to be distinctly 

 affected, as by light. Another plate had been, at the same 

 time, similarly prepared, and inclosed in a dark box, without 

 a magnet, and after a similar length of time this was found to 

 be entirely unaffected. 



The light was also subjected to the test of the convex lens, 

 and was found to be converged and thrown upon the wall in 

 the same way as any other light, but at a considerably greater 

 focal distance, w T hich fact of itself proves that the luminous sub- 

 stance was different from ordinary light. 



By tests similar to those w^hich were employed with the 

 magnet, it w r as subsequently ascertained, with equal certainty, 

 that similar lights were also emitted from crystals. The flames 

 issuing from the points of large crystals were described by 



