THE VOYAGE OF H.M.S. CHALLENGER. 
n-2 
.it thi' bottom of the sea, from the mass of dead calcareous shells which lie there. 
I*, it is the result really established by my analyses? I felt very diffident in trying to 
. :-\v this iju st ion, because, unfortunately, the percentages of lime in my analyses are 
tie 1 -• • rtain <»f all the several numbers; and I consequently decided upon having 
the result put to a test. 
T - aiis\v< r a similar question to the one here discussed with reference to the bromine* 
v. hid prepared three mixtures of Challenger waters, labelled respectively “I.,” 
•nesting of G4 waters, from depths ranging from 0 to 50 fathoms ; “ II.,” consisting 
• f70 waters, from depths ranging from 300 to 1000 fathoms; and “ III,” consisting 
of 70 waters, from depths greater than 1500 fathoms. 
It n aturally suggested itself to me to test the result concerning the quantities of 
1 1 m- by determining this component in these three mixtures with the highest degree of 
1 • i ■ i si- >n, to calculate the results for 100 parts of chlorine and compare the numbers. 
Appendix on the Lime. 
Tii- supplementary analyses referred to were all carried out according to the following 
method, which, after having once been fixed upon, was rigorously adhered to in all 
rases. 
Ileapnts used . — A 20 per cent, hydrochloric acid— 50c.c. left 0*8 mgrm. of fixed 
p sidue. Ammonia of 10 per cent. — 50 c.c. left 0'G mgrm. of a fixed residue, con- 
-isting of alumina and a trace of lime. Oxalate of ammonia, 1 c.c. corresponded to 11 ‘2 
mgrms. of ( 0. 3 grins, of the crystals used for preparing the solution left on ignition 4 
mgrms. of fixed alkali-salts. 
fdtrrs . — The oxalate of lime precipitates were all collected on Swedish filters of 
• • in. radius, previously purified by exhaustion with hot 10 per cent, hydrochloric acid, 
nel v. diing with hot water. 10 such filters left G'5 mgrms. of ash ; whence the amount 
• •f ash per filter = 0*G5 ; the value 07 mgrm was adopted. 
Met/e*I. Al*out 500 gnus, of the sea-water are weighed exactly, mixed with 15 c.c. of 
• ! ai- acid, and boiled for fifteen minutes to expel the carbonic acid. The liquid 
i allowed to »■< *» il, .supersaturated by addition of 1 00 c.c. of ammonia, mixed with 180 c.c. 
' of ammonia, and allowed to stand cold over two nights. The precipitated 
- it- then filtered off, ignited over the gas blowpipe, and weighed as crude lime. 
I "' id' lime is then transferred to a beaker, slaked, and dissolved in 5 c.c. of 
id. The -olution is mixed with 7 c.c. of ammonia, the excess of ammonia 
• ! tin pn • ipitate, which contains the silica, alumina, and ferric oxide of the 
Itered oil and washed. This precipitate is redissolved in 2 c.c. of hydro- 
i‘d p produced by adding 4 c.c. of ammonia, and expelling the excess of 
■ It i- collected on a filter, ignited, and weighed as “ scsquioxidcs.” 
• Smi chnptor on Bromine, p. 89; el ntq. 
