OF ARTS AND SCIENCES. 77 



family had ordinarily been at rest twelve hours in the main and lateral 

 pipes. In some instances it had doubtless been longer at rest; and 

 yet, so far as I have been informed, but one well-established case of 

 lead disease is known to have occurred from the use of this water. 



"Table XVII. — Determinations of Lead in the Croton Water of 

 New York. — Drawn, after thirty-six hours' exposure, from leaden 

 pipes, at seven different localities, in the neighbourhood of John Street. 



Botlles. Volume. Volume. 



1. 500cc. reduced to lOcc. gave, of Sulphide of Lead, 00 



" lOOOcc. derived from bottles 1,2, and 3, concentrated to 10cc.,gave, 

 with hydrosulphuric acid, a precipitate which, ignited with saltpetre 

 and redissolved, gave, with bichromate of potassa and hydrosulphuric 

 acid, distinct precipitates of lead. The whole quantity equalled about 

 0.000 Igr., or for a gallon 0.00045gr. 



" Determination of Lead in the Schuylkill Water of Philadelphia. 

 — According to Professor Booth, 100 apothecaries' ounces, after ex- 

 posure 36 hours in leaden pipe, a year and a half in use, concentrated 

 to the bulk of half an ounce, gave not the slightest discoloration after 

 transmitting hydrosulphuric acid through it for an hour. 



" Troy Reservoir Water. — 2000cc., 24 hours at rest in leaden 

 pipes several years in use, gave, when concentrated to one hundredth 

 of its volume, no trace of lead. 



" Table XVIII. — Determinations of Lead in Jamaica Water 

 served through leaden Pipes in the City of Boston. 



LL \ ■^ 1 Oil Exposed to Gave of Sulphide 



"Aprdl3th. the Lead. of Lead. 



No. 6 Hudson Street, 200cc., 12 hours, reduced to 20cc. 00 



No. 10 " " " " " " 00 



No. 98 " " " " " " 00 



No. 800 Washington Street, " " " " 00 



No. 10 Tyler Street, " " " " 00 



" April 13th. Worcester Railroad Depot, lOOOcc, exposed to the 

 lead 36 hours, reduced to 20cc. gave, of sulphide of lead, OOgr. 



