Vey 
Although we see by referring to these analyses, that several 
of the well-waters of this district are superior to the water supplies 
of Scarborough, or even of Glasgow, yet in a few cases the wells 
are situated in places which are not eligible, and which render it 
probable that they may occasionally receive objectionable drainage, 
although free from it at the time of the analysis,and it therefore 
follows that it is important to note the positions of the source of a 
sample of water, in addition to the results we obtain at a particular 
time by analysis; or to analyse the water upon more than one 
occasion, and especially in the summer months. 
You will observe that the numbers given for ammonia are 
small, and refer only to “parts in one hundred million parts of 
water,” and it will, no doubt, occur to you that the method adopted 
for the determination of ammonia must be very delicate, or that 
the results may in many instances be faulty. The test for ammonia 
is certainly extremely delicate—one of the most sensitive tests 
which chemists possess. It is known as Nessler’s Test, and we 
are capable of detecting by it exceedingly minute traces of ammonia. 
(Experiment made showing the presence of o’oor part of grain of 
ammonia in 10,000 of water.) 
I shall not now refer to the other processes involved in water- 
analysis, but, in concluding this part of my subject, I may quote a 
remark of Professor Chaumont, of the Army Medical School, 
Netley, as given by him in a paper before the Congress of the 
Sanitary Institute at Croydon last October. He said, “‘I consider 
that chemical and microscopical research in the direction of water- 
analysis is of considerable value, but the value has, in my opinion, 
been both over-rated and under-rated. Thus, it has been over- 
rated when chemists have proposed to lay down certain hard and 
fast lines as to the quantity of constituents considered admissible.” 
These words are well worth remembering, especially by those who 
execute rough analyses in their capacities as Medical Officers of 
Health. It is not sufficient to obtain even accurate results in 
chemistry, without fully considering the circumstances which may 
be the foundation for them, and this is especially the case in 
water-analysis, where the same constituents may be derived from 
various sources. 
