594 TRANSACTIONS OF THE 



dividends. Steam-carriages have not had a fair trial. They have not been 

 fully t'ested yet, but will soon be in more general use. 



The subjects selected for the next evening were, "Fire Escapes " and 

 "Iron Buildings," after which the Association adjourned. 



Polytechnic Association op the American Institute, ) 



April Idth, 1860. } 



Professor Mason, Chairman. Benjamin Garvey, Secretary pro tcm. 



Mr. Bruce gave an account of Mono Lake, which is situated near the 

 new silver mines in California. He had received a description of it from 

 his sons, who reside in California. The lake is about six square miles in 

 extent. It has no visible outlet, but the waters appear to flow from the 

 circumference to the centre, and there to find a subterraneous outlet. One 

 peculiarity of the water is, that it removes all corns and calosiiies from the 

 feet of persons wading in it ; and that it reduces the leather of bqots to 

 the consistence of wet brown paper. 



The water is apparently strongly alkaline, as clothing may be washed in 

 it by being simply rinsed. Some colors are discharged in the operation. 



He had received by letter a specimen of a substance found on the sur- 

 face of the lake in great abundance. This substance is gathered and 

 stored by the Indians for food. It is composed of the nymphse of a pecu- 

 liar kind of fly, which is said to breed in the waters, and which is the only 

 living thing known to exist in Mono Lake. It must be nutritive, for when 

 tried out it yields seventy-five per cent of good burning oil. Thousands 

 of tons of this substance can be collected every season, as the whole sur- 

 face of the lake is covered with it, and the waters at the surface are thick- 

 ened with it to the consistence of meal gruel. 



Dr. Stevens had seen the specimen alluded to, and considered it the cast 

 off cases of the nymphrc. The Digger Indians use it for food. 



The alkaline properties of the water are doubtless due to the salts washed 

 out of the shales, the same way as the salt lakes and valleys of the west 

 are formed. The alkalies were originally derived from the ocean, and are 

 •vjashed back again from the land. When, therefore, there is a direct com- 

 munication between any body of water and the ocean, provided that body 

 of water be above the level of the ocean, the water is fresh. This is the 

 case with the waters of the Onondaga Valley, which are two hundred feet 

 above the level of the sea. Wherever salt wells have been sunk to the 

 level of the sea the waters have become fresh. 



. Mr. Degroot and Dr. Trask say that the oil expressed from the substance 

 from Mono Lake is an animal oil. 



The Lake Mono lies due east of Marysville. 



Mr. Whittemore stated that insects are used as food by Indians in 

 Washington Territoi-y. He has seen them so used on the sea coast, and 

 between the Sierra Nevada and Shore Range. 



