SCIENTIFIC SUMMARY. 
263 
►Some varieties of this ore are remarkable for the way in which they break 
up into small brilliant particles. This is the ore employed by the artificial 
florist. We learn that many tons of this lead ore have lately been used in 
this country and in France for this apparently trivial purpose. 
Lead Pipes. — The action of water on lead has not unfrequently led to very 
unpleasant results. J. R Nichols, an American chemist of some standing, 
calls attention to the fact, that leaden pipes are most acted upon by the 
water flowing through them when they are bent at an acute angle. Whether 
this is due to a change in the structure of the lead, or to the mechanical 
action of the water at the point where it is made to turn, is not certain. The 
evidence, however, is satisfactory, that the lead is more rapidly corroded at 
these bends than in any other part. The public should, therefore, see that 
the plumber twists the pipes supplying houses as little as possible ; and that 
where a turn is absolutely necessary he should be instructed to make it as 
gradual as the circumstances of the situation admit, at all times avoiding 
acute angles. 
Artificial production of Crystalline Minerals. — H. Saint-Claire Deville has 
recently obtained, by the action of chlorhydric acid gas upon metallic oxides, 
heated in a platinum boat contained in a tube of porcelain : stannic acid 
in beautiful crystals of the same form as the native oxide ; titannic acid in 
brilliant crystals of a blueish tint ; protoxide of manganese in beautiful emerald- 
green octahedra ; specular iron, in fine crystals like the Elba ore ; and some 
others. Deville suggests that gaseous emanations, as, for example, chlorhydric 
acid, may play an important part in geological phenomena, and may conduce 
to the formation of many crystalline minerals in nature. 
The Indian Coal Fields. — Very loose and imperfect statements respecting 
the quantity of coal in India have been put forth from time to time. Pro- 
fessor Oldham, Director of the Geological Survey of India, now, for the first- 
time, furnishes exact returns for the last three years. 
1858. 
1859. 
1860. 
MAUNDS. 
MAUNDS. 
MAUNDS. 
Kaniganj Coal Field 
5,917,000 
8,949,600 
8,559,097 
Bajmalial Hills 
219,000 
843,000 
1,222,860 
Kurhurbari 
4,000 
108,182 
275,256 
Palamow 
— 
28,648 
30,900 
Sylhet Hills 
22,319 
32,498 
Total in Maunds ... 
6,163,319 
9,961,928 
10,088,113 
„ in Tons 
226,140 
365,575 
370,206 
The other known coal-fields of India are very insignificant, and there 
appears to be no probability of ever greatly increasing the supply of fossil 
fuel in India. 
The Each Oils of America. — Considerable interest has been excited by the 
discovery of many remarkably productive springs of mineral oil in several 
NO. II. T 
