- 
54 REPORT—1858. 
mosphere? Or, did plants generally, or some in particular, assimilate this free 
nitrogen? 
As already intimated, some of the points which had been alluded to were at the 
present time under investigation ; the authors having in this the able cooperation of 
Dr. Pugh. Others, it might be hoped, would receive elucidation in the course of 
time. There of course still remained the wider questions—of the original source, and 
of the distribution and circulation, of combined nitrogen, in the soil, in animal and 
vegetable life on the earth’s surface, and in the atmosphere above it. 
On the Action of Hard Waters upon Lead. 
By W. Lauper Linpsay, I.D., FLAS. 
It is, and has long been currently believed,—1. That where there is free access of 
atmospheric air, pure or soft waters, that is waters absolutely or comparatively free 
from saline ingredients, readily corrode or erode lead, and become impregnated, some- 
times to a poisonous degree, with some of the salts thereof. 2. That the rapidity 
and extent of this solvent or corrosive action are proportionate to the purity of the 
water, that is, its freedom from neutral salts. 3. That impure or hard waters, that 
is waters containing a considerable amount of neutral salts, do not so affect or become 
impregnated with lead. 4. That such waters are prevented from acting on lead by, 
or in virtue of, their saline constituents, which exert a sort of protective or preserva- 
tive power in regard to the lead. 5. That if a given water does not within a short 
period cause a white coating on freshly-burnished lead plates or rods, it may be 
regarded as destitute of any corrosive action, and may therefore be safely allowed 
to be kept in leaden cisterns and transmitted through leaden pipes. 
The author’s experiments and inquiries have led him to the following somewhat 
opposite conclusions :—1. That certain pure or soft waters do not act upon lead. 2. 
That certain impure or hard waters, in some cases containing abundance of the very 
salts which are generally regarded as most protective or preservative, do act upon lead. 
3. That the rationale of the action in these anomalous or exceptional cases is very 
imperfectly understood. 4. That experimentation on the small scale and for short 
periods is most fallacious, and frequently dangerous, in regard to the conclusions 
thence to be drawn. 5. That water may, under certain circumstances, and to cer- 
tain extents, contain lead without necessarily being possessed of poisonous action 
on the human system. 6. That water contaminated with lead may deleteriously 
affect certain members or individuals only of a community, family, or household. 
7. That the use of water so contaminated is the obscure cause of many anomalous 
colic and paralytic affections. 
One chief object of the paper is to illustrate the second of the latter propositions, 
viz. that hard waters frequently do act upon lead. The author tabulates the various 
theories or explanations that have been or that may be advanced to account for the 
action of such waters upon lead, as follows :— 
1, Galvanic action from the contact of different metals, or of different qualities of 
the same metal, under water. 
’ 2, Unusually small quantity of,— 
a. The neutral salts generally, or in the aggregate. 
bd. Particular neutral salts, such as the carbonates and sulphates. 
3. Use of leaden covers to cisterns. 
4. Long exposure of still water to the same surface of metal, as in the storing 
up of water in lead cisterns. 
5. Great extent of surface of metal exposed to the action of water. 
6. Unusually large proportion of carbonic acid in the water. 
7. Unusually large proportion of atmospheric air in the water. 
8. Presence of nitrite of ammonia in the water. : 
9. Presence of acids, derivable from decaying or dead animal or vegetable matter. 
10. Presence of foreign bodies or accidental impurities. 
11. Chemical or electro-chemical causes, with which we are at present unac- 
_quainted. 
The author refers to the first of these theories or explanations—galvanic agency 
