LAMP SHELLS. 41 



water form has been found boring in the dead trunks of trees. 

 Pliny was probably among the first to place on record the 

 luminosity of this little borer, having stated that it shone 

 in the mouths of those who ate it ; and its phosphorescence 

 has been studied by R^aumer, Beccaria, Marsilius, Galeatus, 

 Montius, and others in modern times. One of Beccaria's 

 experiments was to ascertain how the light affected certain 

 colors. He secured a Pholas in a dark spot, and placed in 

 its light ribbons of various colors. The white ribbon shone 

 most brilliantly, the yellow next, and the green next, while 

 others were so indistinct as to be hardly noticeable. Sub- 

 stituting liquids for the ribbons, the result was the same. 



Beccaria also made one of the first practical applications of 

 the phosphorescent Pholas, demonstrating that it could be 

 used as a lamp. This was accomplished by placing one in 

 seven ounces of milk, which rendered the latter so luminous 

 that print could have been read by it, the milk appearing 

 almost transparent. So it is within the bounds of possibility 

 to write a post-^mortem description of the Pholas by its own 

 light. 



It is evident from these simple experiments that the dis- 

 covery of the secret of phosphorescence, and its practical 

 application to the wants of mankind, would result in revolu- 

 tionizing present systems, -^- a heatless, inexpensive, unextin- 

 guishable light being the perfection of possibilities in this 

 direction, — and it is not improbable that the experimentalists 

 of olden times may have had this in view when making their 

 investigations. Both Reaumur and Beccaria attempted to 

 render the light of this animal lamp permanent. By placing 

 one in honey, the luminosity was apparently preserved for a 

 year, the light re-appearing whenever the moUusk was placed 



