147 
During the greater part of the day a strong current setting 
in from the south, probably from the Atlantic, flows past 
the ship into the North Channel, and thence again into the 
Ocean. The water therefore taken for analysis was origin- 
ally that of the deep ocean, which had traversed almost the 
entire length of the Irish Channel, and had consequently 
been exposed to all the influences due to the neighbouring 
sea-board, and to the influx of the numerous rivers along 
the coasts. 
The water was obtained in the early part of January, 
1870; the meteorological conditions at the time of collec- 
tion, and for some time previously, were in no wise remark- 
able. The analysis was commenced immediately on receipt 
of the water. Its specific gravity compared with distilled 
water, free from air, and possessing the same temperature, 
was found to be 
At 0° C 1-02721. 
At 15° C 1-02484. 
These numbers differ but slightly from that usually accepted 
as representing the mean specific gravity of the water of the 
ocean. The water of the Atlantic, according to Yon 
Horner, possesses the specific gravity 1-02875 at 0° C : that 
of the English Channel at 15°-5 was found by Schweitzer to 
be 1-0271 : on nearing the land the specific gravity fell to 
1-0268. 
Full details of the methods of analysis employed are given 
in the original paper. The following synopsis shows the 
mean results of the determinations : the numbers express 
the amount of the various ingredients in 1000 grams of the 
sea-water. 
1 Chlorine 18-62650 
2 Bromine ‘06133 
3 Sulphuric Acid (S0 4 ) 2-59280 
4 Lime (total) -57512 
5 Calcium Carbonate -04754 
