10 
the voyage of h.m.s. challenger. 
iinm-'iii solution, of which 1 c.c. corresponded to 14 mgrms. of lime. The mixture was 
l! a. .1 i.. -t and -•■/</ overnight ; the oxalate of lime was then filtered off, washed, ignited, 
and w j!i. d as lime. The filtrate and wash -waters were mixed with 15 c.c. of 10 per 
ammonia, and 10 c.c. of phosphate of ammonia (1 c.c. corresponding to 20 mgrms. 
• M < h uni allowed to stand (cold) over night. The precipitate was filtered off, washed 
with dilute ammonia, ignited, and weighed as pyrophosphate. 
I- ■ first scries of analyses (21 samples) this method was applied exactly according 
t v. description. 1 was quite aware that oxalate of lime, precipitated under the 
. um-tanecs, of necessity carries down some of the magnesia, but thought I had better 
n • lim at a higher precision at the certain expense of constancy in the results. When 
subsequently the process was looked into synthetically, it turned out that I was not far 
nj in estimating the loss of magnesia involved in it; but the experiments brought to 
1 _iit another emir, affecting the lime only, for which I had not been prepared. The 
u ;i'd “ Cat )’’ contained a considerable admixture of carbonate of soda, showing that 
tie oxalate of lime must have carried down a corresponding proportion of soda as 
oxalate. In the second series of analyses (30 samples), the crude lime precipitates were 
carefully collected, mixed, and analysed as follows : — 
Tie mix- -1 lime precipitates w r ere reignited to bring them back to a constant weight 
l-f--r- an d \ -i The hydrochloric solution of a known weight was boiled to expel car- 
b n el, ammonia in excess added, and the excess boiled off again to bring down a 
trace of alumina, which was filtered off. 
dli lime wn- th'-n precipitated with excess of oxalate of ammonia, ignited and 
w ■■-!>■ d i- lim-. Phis lime was redissolved and reprecipitated as oxalate, the latter 
converted into lime and weighed. 
Residts. 
1. Crude precipitate taken, . . , 0-4062 grms. 
2 Line-, CaO, fiwt precipitation, . . 0-3768 „ = 92'76 per cent, of (1) 
3 „ second „ ... 0-3746 ,, = 92-21 per cent, of (1) 
I t !tnt- from (2) was evaporated to dryness, the ammonia salts burned off, the 
r . lm r- dissolved, and the magnesia separated out as ammonio-phosphate. The 
-U u t- determined in an aliquot part of the same filtrate. 
hound in 100 “parts of Crude Lime , including the Filter-aslies. 
1’ure lime, CaO, . . . . .92-21 
Magnesia, ..... 2-34 
Carbonate of soda, Na,CO it .... 5-12 
Alumina, silica, dec., and error, .... 0*33 
10000 
T sk i.j L X- m-aning the weight of “ CaO + filter- ash,” and M as the weight of the 
■MgDuna calculated from the !i fi--- pyr->pliospliatc obtained in a given analysis, the 
