372 Proceedings of the Royal Society 
In reviewing the results of the determination of the specific 
gravities of the samples of water, it was observed that the fresh 
water supplied by the Ness and Beauly Kivers possesses the mean 
specific gravity of 1000*44 ; and the strongest sea water — viz., that 
of Burghead — shows a specific gravity of 1025*13. The many 
samples of water collected from the Firth of Inverness have a specific 
gravity which is considerably beyond the mean of fresh and salt 
water, and in the majority of instances closely approaches the 
specific gravity of the sea water taken off Burghead, and which is 
undoubtedly sea. 
The results of the determination of the respective amounts of 
saline matter dissolved in the various waters entirely corroborates 
the conclusions arrived at from the consideration of the specific 
gravities, — viz., that each sample of water, as collected from the 
Firth of Inverness, is decidedly more salt than fresh, and in most 
instances the water is practically the strength of sea water. The 
lowest proportion of saline matter in the water of the Firth of 
Inverness is nearly eight hundred times the quantity found in the 
water of the Kiver Ness. 
The relative amount of chloride of sodium, as indicated by the 
proportion of chlorine in the waters from the Kivers Ness and 
Beauly, is so minute that it only amounts to about half a grain 
of chloride of sodium in the imperial gallon ; whilst the lowest pro- 
portion of chloride of sodium (calculated from the chlorine) which 
is present in the water of the Firth of Inverness is equal to 1574 
grains in the imperial gallon. 
The water, therefore, obtained from any part of the Firth of 
Inverness, contains more than two thousand times the quantity of 
chloride of sodium, in a given volume or weight, than that which 
is present in the waters of the Ness and Beauly. In this vast 
increase in the proportional amount of common salt, there is the 
strongest corroboration of the greater prevalence of salt water in 
the Firth of Inverness ; and, judging alike from the specific gravity, 
the total amount of saline matter dissolved in the water, and the 
large proportion of common salt, there can be no doubt that the 
Firth of Inverness is sea, and that it will he found by naturalists 
to afford to marine flora and fauna all the required strength and 
chemical properties so essential for the unimpaired growth, de~ 
