17« UOVAL 80CIETY OF CANADA 



As will be observed the analyses here presented extend over a 

 number ol' y care, and represent the water as collected at different 

 .reasons. The data show tliat the character is that of an "upland, 

 peaty " water. It is evidently of fairly constant composition, judging 

 from the hygienic standpoint, and can be classed as a good, potable water. 

 The most notable feature of these analyses is the high percentage of 

 organic and volatile matter (indicated by the figures in the columns 

 marked Albuminoid Ammonia and Loss on Ignition), as compared with 

 the total solids which are, comparatively speaking, very low. This 

 organic matter is chiefly, if not entirely, of vegetable origin, and, so far 

 as is known, is of a harmless nature. The free ammonia, nitrogen as 

 nitrates and nitrites and chlorine are low, indicating freedom from 

 excrementitious matter. The reason for the comparatively high 

 albuminoid ammonia has already been accounted for in referring to the 

 dissolved vegetable organic matter present. The total solids, as already 

 remarked, are very low, even for a river water. They vary slightly with 

 the season of the year, but always indicate a water that would prove 

 useful for domestic and manufacturing purposes. 



The determinations of the mineral constituents of the Ottawa, 

 the estimation of which forms the basis of this investigation, was under- 

 taken at the suggestion of Dr. R. A. Daly, geologist to the International 

 Boundary Commission, and the raison d'etre can best be given by quot- 

 ing from a letter from him to one of the writers in this connection. 

 '^ The purpose of the two (winter and summer water) analyses is to 

 secure an approximate annual average composition of the dissolved 

 materials in the Ottawa as what may be called a typical pre-Cambrian 

 river. I mean by this that the Ottawa above the Capital drains an 

 immense and nearly average rock area of the pre-Cambrian terrane in 

 Canada. The later (Palaeozoic) formations occur in but very small 

 or negligible patches above Ottawa City, while the various Huronian 

 and Laurentian formations are mostly all represented on a .great scale. 

 This area of pre-Cambrian rocks drained by the Ottawa is certainly one 

 of the very largest known to be underlain by these old formations within 

 a single river-basin. 



The samples of water from which tlie determinations were made 

 were collected by Dr. Daly from the main course of the river above the 

 Chaudière Falls at two seasons of the year. The first sample was taken 

 on March 12th, 1907, before the melting of the snow had commenced 

 along the iipi)or strotclies of the tril)utaries of tlie Ottawa, or the ice 

 on the river itself had " broken up." The river was then passing 

 through the stage of the lowest water known in the last fifty years. 



