354 BOTHAMLEY \ MINERAL WATERS OF ASKERN IN YORKSHIRE. 
when the water is distilled with a small quantity of sodium carbonate 
ammonia is evolved in relatively large quantity. 
In view of these facts it would be useless to examine the organic 
matter left in the residue obtained by evaporation in the ordinary 
way, or to examine the products obtained by the distillation of the 
water at the ordinary temperature and pressure. The only method of 
ascertaining the real nature of the dissolved organic matter would 
seem to be to evaporate a large quantity of the water in a vacuum at 
the ordinary temperature. I was unable to carry out this investiga- 
tion before leaving Yorkshire for the south of England, but I am of 
opinion that it might lead to results of considerable value. 
The oxygen absorbed by the organic matter, as estimated by 
means of an acidified solution of potassium permanganate at the 
ordinary temperature, and after making the correction necessitated 
by the presence of sulphuretted hydrogen, was as follows : — 
Oxygen absorbed by 100,000 parts. 
Mather Close. Charity. Terrace. Manor. Pool. 
578 ... 4-92 478 ... 4*24 ... 0'015 
The contrast between the organic purity of the water of the 
Pool and the large quantity of dissolved organic matter in the waters 
of the adjacent wells is very remarkable. A reference to Table A 
will show that the Pool water contains a large proportion of 
calcium sulphate, and it is probable that this compound precipitates 
the organic matter. 
The Sulphuretted Hydrogen. 
The whole of the hydrogen sulphide is present in the form of 
dissolved gas, and can be expelled by passing a current of an in- 
different gas through the water for some time. 
Neither sulphides nor thiosulphates are present in the waters. 
After complete removal of the hydrogen sulphides, the water dis- 
colourises a not inconsiderable quantity of iodine solution, but this 
absorption of iodine is due to the organic matter, and has, of course, 
to be allowed for when estimating the sulphuretted hydrogen. 
The variations in the quantity of hydrogen sulphide are of much 
scientific and practical interest. The following table shows the 
quantity of sulphuretted hydrogen in cubic centimetres per litre, and 
