5G4 Abstract Report of Agricultural Discussions. 
case of many M aters by the perfect filtration which they undergo in 
passing through a porous rock or a bed of jwrous sandy soil. Surface 
springs invariably contain organic matter in solution, and sometimes 
if the filtration has been imperfect, a farther quantity in suspension. 
Wherever men or animals cougrcgate refuse matter accumulates, and 
finds its way into surface wells. An admirable provision is made for 
the destruction of these matters. Wherever the drainage is good the 
air which passes along with water through the porous soil almost com- 
pletely decomposes the organic matter, or at any rate makes it inno- 
cuous. We have, then, in the absence of putrescent animal matter, 
a very good indication that the water is serviceable for drinking. 
The presence of a bad smell invariably indicates something wrong in 
water, though its absence affords no assurance that all is right. Organic 
matter, however, though ahvays unpleasant is not always injurious. 
That which occurs invariably in localities where peat abounds in the 
soil is, I believe, not directly injurious to health, though its presence 
in water is undesirable, because experience has shown that organic 
matter of any kind has an injurious effect on the leaden pipes through 
which water is conveyed to our houses. 
It is, then, important to discriminate between the different kinds 
of organic matter that we are likely to meet with in water ; and an 
excellent method of doing this is to evaporate from a couple of pints 
to two ounces. If during the evaporation the water becomes coloured 
it will generally be found that it contains an amount of organic 
matter which is injurious to health ; if it remains colourless, or 
becomes but slightly coloured, the absenco of organic matter of an 
injurious nature may be safely predicated. If after the water has been 
perfectly evaporated to dryness, the matter which remains, on being 
heated, gives off a smell like burnt feathers, which is characteristic of 
the presence of nitrogenous matters, we have in this at once a proof 
that the organic matter is of animal origin, and the water should be 
at once rejected for drinking purposes. 
Softness is a quality in water that depends entirely upon its com- 
position. Nowhere in nature do we find water in a perfectly pure 
state. Even rain-water, which has undergone a kind of natural dis- 
tillation, contains certain atmospheric impurities which, though useful 
in an agricultural point of view, are undesirable in drinking-water. 
Rain-water is an excellent solvent for many combinations that occiu' 
in tht) soil, acting not only on saline substances like common salt, or 
on sulphates, such as sulphate of magnesia or sulphate of soda, but also 
on mineral matters, which are usually regarded in common life as 
insoluble. 
We may instance carbonate of lime, one of the principal consti- 
tuents of all hard waters. Practically speaking, it is insoluble in pure 
water, since 25,000 parts of the water are required to dissolve one part 
of that substance. But we are to remember that rain-water invariably 
contains carbonic acid in solution, and in virtue of its presence exerts 
a power of dissolving carbonate of lime with considerable rapidity. 
It is the carbonic acid in rain-water which accounts for the invariable 
presence of carbonate of lime in considerable quantities in all spring 
