i68 Dr. Hulme's Experiments and Observations 



Roe of Mackerel. 



Exper. g. With Epsom salt two drams, and water two 

 ounces. On the second night, the liquid, when agitated, was 

 exceedingly bright ; on the third, the same ; and on the fourth 

 and fifth, still lucid. 



The Tadpole. 



Exper. 10. It occurred to my mind, in the year 1797, to try 

 what effect a saline menstruum would have upon the tadpole. 

 Accordingly, I procured some tadpoles on the 10th of June, and 

 put six of them into a solution of two drams of Glauber's salt 

 in two ounces of water. On the 1 ith, in the evening, the men- 

 struum was dark; on the 12th, after shaking the phial, I was 

 agreeably surprised to find it impregnated with light; on the 

 13th, the light was so abundant as to float on the top of the 

 menstruum; on the 14th, the same phenomenon appeared; on 

 the 15th and 16th, it was still present; on the 17th, the lucid- 

 ness began to diminish; on the 18th, it was faint; and on the 

 19th it had vanished. 



Exper. 11. On the 11th of June, six other tadpoles were 

 dropped into a solution of one dram of common salt in three 

 ounces of water. On the 12th and 13th, the menstruum was 

 dark ; on the 14th, it had extracted from the tadpoles a very 

 beautiful bright light ; on the 15th, the menstruum was exceed- 

 ingly luminous ; on the 16th and 17th, nearly the same: the 

 light then gradually faded, so that on the 21st it was merely 

 visible ; and on the 22d it disappeared. 



Exper. 12. On the 21st of June, the above two experiments 

 were repeated ; when the tadpoles remained in the menstruums 



