210 MOSQUITOES 



the well known seacoast resort directlj^ east of Norfolk, 

 Ya. Behind the hotels at this place, in former days — the 

 hotels themselves fronted npon the beach — was a large 

 fresh water lake, which, with its adjoining swamp, was a 

 source of mosquito-supx^ly, and it was further feared 

 (although this was before the mosquito-dissemination of 

 malaria was proven) that it made the neighborhood mal- 

 arious. Canals were cut, and the water of the lake was 

 changed from a body of fresh to a body of salt water. 

 The lake is now supplied with salt water at daily high 

 tides by an underground feeder. Crabs and small tish 

 occur in the lake in numbers, and no mosquito larvse 

 are to be found even in August, even in the swampy 

 places at the lake border. The water itself is very salt to 

 the taste, and samples which have been tested at my re- 

 quest by Mr. E. E. Ewell, a chemist, showed that the 

 total chlorine contained in the samples, calculated as so- 

 dium chloride, is equivalent to 22.88 grams of that salt per 

 liter, or 1,336 grains per United States gallon, or 3.05 

 ounces (avoirdupois) per United States gallon. The chlor- 

 ine contained in sea-water is equivalent to 31.15 grams of 

 sodium chloride per liter. The sam^^les from Virginia 

 Beach, therefore, contained approximately two-thirds of 

 the quantity of salt usually i:)resent in the sea-water. 



Even where states or communities cannot be induced to 

 take up the question of marsh drainage and diking, it is 

 possible for public-spirited individuals of means to do 

 work in this direction which Avill count. For example, it 

 is planned by a company of wealthy men who have sum- 

 mer homes on the north shore of Long Island, in the 



