290 



agency of electricity. Cumulus clouds were always highly charged 

 with electricity. The particles of air in them would be mutually 

 repulsive, and produce an expansion and consequent rarefaction 

 to an indefinite extent, which enable the cloud to bear along the 

 bodies taken up by whirlwinds. 



Dr. Gould presented, in the name of Capt. Stribling of 

 the United States Ship Ohio, a donation of gold sand from 

 the Mormon diggings. The thanks of the Society were 

 voted for the donation. 



Dr. Kneeland presented, in the name of Mr. George 

 Ditson, two Hindoo skulls. The thanks of the Society 

 were voted for the donation. 



Mr. Henry D. Morse was elected a member of the 

 Society. 



May 15, 1850. 



C. T. Jackson, Vice-President, in the Chair. 



Thirteen members present. 



Dr. Burnett exhibited a living specimen of the Fire-fly, 

 from Cuba, Pyrophorus phosphorus, and gave an acccount 

 of its light-producing structure. 



The luminous spots in this species are situated at the posterior 

 angle of the thorax. By Spyx and Matteucci they have been 

 described as made up of of a globular, phosphorescent matter. 

 Dr. Burnett had dissected these spots immediately after the 

 death of the animal, and had examined them under the micro- 

 scope and by means of chemical reagents. The phosphorescent 

 spot was found to be made up of fat globules permeated by 

 tracheee, and showing no trace of nerves or bloodvessels. It is 

 difhcult to say in what precise portion of this structure the phos- 

 phorescence is situated, as reagents which destroy one or the 

 other extinguish the light. It is probable that the phenomenon 



