REPORT ON THE COMPOSITION OF OCEAN-WATER. 
11 
corrected values I/ = 0*922lL and Mf = M. + 0'0234L should come nearer the truth than 
L and M. These corrections accordingly were applied to the second series of analyses. 
When the third series of (26) samples came to hand, I might have applied the same 
formulae ; but as I had some doubts about the perfect soundness of the work upon which 
they were based, I preferred to analyse the collected precipitates again, including this 
time the pyrophosphates of magnesia. As a result I found in 
The Crude Lime Precipitate, including Filter-ash. 
I. 
II. 
III. 
lime, CaO, ..... 
91-58 
91-21 
91-23 
Silica, Alumina, Ferric oxide, Si0 9 , A1 2 0 3 , Fe 2 0 3 , 
1-35 
1-72 
2-02 
Magnesia, MgO s , .... 
2-18 
2-11 
2-34 
Potassium carbonate, K 2 C0 3 , . 
0-65 
0-53 
0-28 
Sodium carbonate, Na 2 C0 3 , 
5-26 
5-96 
5-92 
101-02 
101-53 
101-79 
The excess over 100 per cent, is partly due to the fact that the carbonic acid 
in the alkaline carbonates was only calculated from the potash and soda, as determined 
by the platinum process. The “ lime ” in each of the three analyses was redissolved in 
hydrochloric acid, reprecipitated as oxalate, reduced to lime, and weighed in this purified 
condition. Calculating from this latter weight, the percentages come down to 
I. II. III. 
Pure lime, . . 9097 90-92 90-95 
With regard to the pyrophosphate of magnesia, I could not see my way towards an actual 
method of analysis sufficiently simple and precise to promise results worthy of serving as 
a basis for a correction formula. I therefore satisfied myself with merely dissolving a 
known weight of (mixed and re-ignited) substance in pure concentrated vitriol, main- 
taining a temperature somewhat below boiling for three or four hours, diluting, filtering 
off a minute precipitate, and reprecipitating with ammonia and a little phosphate of 
ammonia. The ignited precipitate was weighed as presumably purified pyrophosphate. 
Of crude pyrophosphate 2*5106 grms. (including the filter-ash) were taken, and 
the sulphuric-acid solution made up to 251*45 grms. with water. Of this mixture aliquot 
parts were analysed with the following result : — 
Solution taken, ..... 
51-729 
51-735 
51-734 
51 -731 grms 
Magnesium pyrophosphate obtained, 
0-5145 
0-5133 
0-5143 
0-5133 „ 
Per cent, of “pure” magnesium pyrophosphate, 
99-69 
99-36 
99-56 
99-37 
Mean, . 
99-49 
From the above analyses we see that the amounts of crude 
lime are 
liable to the 
correction 
(Crude lime) x 0*91 =pure lime. 
