166 Abstracts of Foreign Memoirs. 
circumstances under which rock-salt and various combinations of salt 
are found are carefully described (ch. xiii.). HEmanations from the 
interior of the earth (whatever and wherever that may be) are 
believed to be the sources of salt as well as of other contents of 
springs. In another chapter M. Lecoq expresses his belief that the 
sea was originally fresh, and has become salter as time advanced. 
The salts of lime and magnesia naturally occupy a considerable 
space in any account of mineral waters and their operations. They 
are universally distributed, and in various forms. We do not, how- 
ever, observe anything of novelty in reference to this subject. The 
salts of aluminium are also found in water; and as these are largely 
deposited in various forms, often very complex, wherever hot water 
has passed, they admit of very interesting exemplification, The 
work done by Deville, Daubrée, and other chemists, is quoted; and 
the subject, which is one of great interest, is treated in reference to 
inineral veins. 
Of the metals proper, a considerable number are found in mineral 
springs. M. Lecoq quotes several localities where salts of manga- 
nese occur; and iron is well known to be almost universal. Cobalt 
and nickel have been found at Boulou. Zinc and cadmium are 
probably present in mineral waters near deposits of calamine; and the 
same may be said of chromium. Molybdenum, tungsten, and vanadium 
are not rare; and antimony is occasional. ‘Tin, titanium, copper, lead, 
silver and gold, have all been detected in water; and some of them 
are common in thermal springs. 
Organic matter has been found in mineral waters: it has been 
recognized under various names—barreégine, glairine, &c.; its pro- 
perties being different from different springs. M. Lecoq finds in 
this substance additional evidence in favour of his view that mineral 
waters proceed from beneath all stratified and other rocks forming 
the crust of the earth; for he regards these organic bodies as remains 
of the earliest forms of life introduced upon the globe. According 
to M. Filhol, who has examined these substances, they are most 
abundant in the hottest springs. A spring at Arles is estimated to 
yield 754 kilo. (1,663 lbs.) a day of organic matter; another at 
Thuies 2,800 kilo., 6,176 lbs. (55 cwt.) a day. These results cannot 
be altogether depended on. The source of this organic matter is by 
no means clear; and the phenomenon is one of extreme interest, 
Mineral springs are not without changes. ‘Their temperature, 
although generally constant, is subject to modification; for some 
have increased, some have diminished, within the limits of observa- 
tion. Earthquakes have not unfrequently affected hot springs. The 
volume of water delivered also changes in some cases with altera- 
tions of the pressure of the atmosphere, and more frequently or 
markedly by earthquakes. Periods of long intermission in the 
running of such springs are not unknown; and alterations in the 
mineral contents have been observed in some very remarkable cases. 
That mineral waters produce very important results on the rocks 
they traverse, has long been known. ‘They often disintegrate, and 
sometimes decompose, even porphyries and granite; they change 
