and Water used for General Purposes. 
155 
were derived from yard-drainage, sewage, or similar objection- 
able liquids. In consequence of these impurities the water was 
positively poisonous, and probably caused the death of the two 
beasts. 
Very soft waters, as mentioned already, not unfrequently 
contain traces of lead in solution. It may be questioned whether 
minute traces of oxide of lead exert a positively injurious effect 
upon health, but there can be no doubt that an appreciable 
quantity of soluble lead-compounds in water affects injuriously the 
health of man and beast. A remarkable instance of water con- 
taminated with an unusually large proportion of oxide of lead 
was brought under my notice some years ago. This water on 
examination was found to contain in the imperial gallon : — 
Grains. 
Organic matter 5*22 
Oxide of iroa "20 
Oxide of lead "47 
Sulphate of lime 3 " 14 
Carbonate of lime 1'31 
Magnesia 1 • 28 
Chloride of sodium 2 ' 30 
Alkaline nitrates 2 "38 
Soluble silica 1"05 
Total solid matter (dried at 130° C.) per gallon 17-35 
It will be seen that this water contained nearly half a grain of 
oxide of lead in the gallon ; and I ascertained that this poisonous 
oxide occurred in solution partly as bicarbonate of lead, partly 
as nitrate of lead. The water was drawn from the leaden 
supply-pipes connected with a well sunk in close proximity to 
a manure-heap, which accounts for the abnormally large quan- 
tity of soluble organic matter in the water. Drainage from the 
(lung-heap evidently passed into the soft well-water, partly in 
an unaltered condition, partly oxidised into nitrates, which, in 
contact with metallic lead, are known to give rise to soluble 
nitrate of lead. Probably the soluble organic impurities in the 
water also acted upon the lead and gave rise to soluble lead- 
compounds. The unfavourable position of the well in this case 
fully accounts for the contamination of the water with injurious 
organic impurities, and the still more poisonous lead-compounds. 
The properties of water, which enable it to act at times with 
unusual vigour upon lead, are little understood, and seem often 
to arise from the accidental action of local causes, such as the 
presence of drainings from dung-heaps and decaying organic 
impurities. These causes are of a kind most to be dreaded in 
the supply of a single residence, in which, as in the case before 
us, the whole volume of water may at a time assume the same 
