It is probable that the returns have never been accurate in regard to the mixed bloods and Indians, but it is the general conclusion that the Indians have been decreasing in number, while the mixed bloods have been increasing.
Mortality is decreasing, but if we may judge from the physical conditions of the recruits the physique of the nation shows little or no improvement.
The conditions of formation and accumulation of petroleum point to the fact that the principal oil fields of the world are merely reservoirs, which will become exhausted in the course of years, as in the case of the decreasing yield of certain of the American fields.
It is still found in the northern counties of England and North Wales, but in decreasing numbers.
Ansdell show that if the gas be subjected to a pressure of 21ï¿½53 atmospheres at a temperature of o° C., it is converted into the liquid state, the pressure needed increasing with the rise of temperature, and decreasing with the lowering of the temperature, until at - 82° C. it becomes liquid under ordinary atmospheric pressure.