PROCEEDINGS OF THE rOLYTECHNIC ASSOCIATION. 



585 



In a report of Major Doug-lass, the Eng-inoer to wliom the Croton supply 

 sliouhl be properly accredited, dated November, 1833, analysis of the 

 Bloecker street and Thirteenth street wells show 80 grains of solid matter 

 in the tirst, and 64.4 grains in the second, per gallon. A previous report 

 makes the Manhattan well 125.8 grains per gallon. 



During the preliminary examinations for the Btooklyn Water Works, 

 various city wells were analyzed, as being most gehcrally used, and gave 

 43.2, 4ti.4, 58.6, and in one case 11 grains per gallon. 



The Beacon Hill well at Boston gave 50 grains per gallon; the Capitol 

 Park well at Albany, 65.5 grains ; wells at Detroit gave 116.4 grains ; at 

 Indianapolis, 60 grains. 



In London, St. Paul's Churchyard well gave 15 grains ; and the Lam- 

 berth Shallow well, 110 grains. 



Six samples of Thames water, reported in 1857, gave an average of 

 2.059 grains organic and 23.281 mineral contents, or 25.34 in all. 



Thr<'e prominent London sewers, analyzed in 1857, gave the following 



results: 



Locality. Organic. Mineral. Total grains. 



Earl 2.738 46.110 4B.84S 



i'ii Icon Brook 3.987 40.146 44;i33 



King's Scholars' Pond 17.750 47.230 64.980 



While this analysis preserts a singular contrast with sources of com- 

 mon public use, and furnishes a severe comment on the delay's common to 

 all projects of sanitary improvement, it must be understood that the same 

 sewers, at other periods of flow, would give very different results, more in 

 keeping with those from other sewers in a more active state of organic 

 discharge. 



Sewage flow, taken in London, in a district aSected by the intermittent 

 water supply, in vogue, gave 96 grains soluble and 28 grains insoluble 

 matter on days of water supply, and 127 grains of soluble and 40 grains 

 insoluble matter at intervening days. 



