30 Proceedings of the Royal Physical Society. 



nation of articles of food and drink, to wliicli subject, it is 

 pleasing to notice, tliere lias been a considerable amount of 

 attention given in late years, resulting, as was liigbly neces- 

 sary in many cases, in greatly improved methods of analysis. 

 As migiit have been expected, water being an article in 

 common use, and being very liable to contamination, has 

 received at least a fair amount of attention, the modes of 

 analysis in the last few years having been very much altered 

 and improved. Formerly, either from mistaken ideas as to 

 the nature of the substances which influenced the character 

 of waters intended for domestic use, or from inability to 

 estimate correctly certain ingredients, the presence or absence 

 of these peculiar constituents, which are by far the most 

 potent causes of bad water, was seldom or never determined. 

 The results of an analysis of water, as reported by chemists 

 a few years ago, and even by some chemists still, show with 

 great minuteness the amounts of the different salts present, 

 a matter the determination of which is a tedious, a trouble- 

 some, and withal a totally useless operation. Besides this, 

 there was introduced at the end of the statement of analysis 

 an undefined and undefinable something known as organic 

 matter, which, however, whatever it was, was certainly not 

 organic matter, as it simply showed the loss after certain 

 allowances and corrections which the water residue suffered 

 on being exposed to a red heat. There could not be a greater 

 fallacy than reckoning this loss as organic matter, and it 

 would be difficult to make a greater mistake than to rely 

 upon this, even if it did show the amount of organic matter, 

 as an indication of the suitability or unsuitability of a water 

 for domestic use. In the accompanying table (A) I show 

 the mode in general use in former years, and still used in 

 some instances in reporting results of an analysis of water. 

 Before referring further to this table, I should remind the 

 meeting that in this paper I am referring to analysis of water 

 intended for domestic use alone, and not for trade purposes, 

 as brewing, distilling, tanning, and the like. From this table 

 it will be seen that in the analysis pursued in eliciting these 

 results, the whole, or the greater part by far of the analyst's 

 care has been lavished in ascertaining the precise number of 



