756 REPORT—1896., 
mined after filtering off the colouring-matter, by titration with arsenious acid. 
For 2 molecules of dehydrothiotoluidine sulphonic acid there were required— 
In the cold —3 atoms of oxygen 
Hot —4 atoms of oxygen 
which corresponds to the following formule for the products : — 
+ 
Ze. s) 
Ne WA Ss 
| 7s 
s | 
CHACHA 0 —=N— 
+ 
First Product. 
a 
= S$ 
ay... KX. ee 
yy 
S 
eager cl) _y_ 
+ 
Final Product. 
8. Abnormalities in the Behaviour of Ortho-derivatives of o-Amido and 
Nitro-benzylamine. By Dr. F. E. Francis. 
9. Nitrates: Their Occurrence and Manufacture. By Wit114m Newron. 
The world’s chief supply of nitrate is that of the northern provinces of Chili. 
The nitrate here occurs in a narrow band, following the eastern foot of the coast- 
line of hills at an elevation of 3,000 to 4,000 feet, and at a distance in a direct 
line from the sea varying from fifteen to thirty-five miles, extending from Pisagua 
in the north, to Antofagasta in the south, about 250 miles. 
Owing to its rainless condition, this plain is almost absolutely devoid of growing 
vegetation. Previous vegetation there has been in abundance, as shown by the 
remains of forests, a few inches below the surface, in addition to which large 
quantities of organic matter are carried down by mountain floods. The decom- 
position of this organic matter forms nitrate in the ordinary way, but the nitrate 
has no growing vegetation to absorb it, and is therefore carried in solution by the 
drainage waters of the west side of the Andes, which are always percolating under 
the surface of the plain, and, at periods of about eight or nine years, even com- 
pletely flood it. These waters collect at the lower side of the plain against the 
coast-hills, and there evaporate under the hot, dry atmosphere. 
The crude nitrate is found under a layer of a few inches of blown dust. The 
first layer of nitrate-bearing strata is extremely hard rock, containing from 10 to 
20 per cent. of nitrates; this rock varies from a few inches in thickness to 16 and 
18 teet, and is bored through to reach the richer material called caliche, which 
contains sometimes as much as 70 to 80 per cent. of nitrate. This layer also 
varies in thickness up to 7 feet. In the extraction the boring is continued through 
this, and the whole mass is upheaved by blasting powder made on the spot. 
The rock nitrate is neglected, and the caliche carted away to the crushers, 
thence to large iron boiling-tanks, a favourite shape of which is 32 feet by 6 feet 
broad, and 9 feet deep. In these are five coils of steam pipes, and the boiling is 
