Rainfall usually increases with increasing altitude up to a certain point, beyond which, owing to the loss of water vapour, this increase stops.
They vary much with the condition of the air as to dust, clouds, water vapour, &c.
Owing to the distance from the chief source of supply of water vapour--the oceans--the air over the larger land areas is naturally drier and dustier than that over the oceans.
The plates of the spectrum of Mars show a much more definite darkening of the 'a' band, and Professor Lowell contends that this can only be due to water vapour in the atmosphere of Mars.
He thought, however, that if water boiled at such a low temperature, then the proportion of water vapourin the air would be increased, as evaporation would be more rapid than on the earth.
The plates of the lunar spectrum show a darkening of the 'a' band, which indicates the presence of water vapour, and we know that is due to the water vapour in our own atmosphere.
He concluded from his experiments that the water vapour present in the air absorbs at least 10% of the heat radiated from the earth within 10 ft.
Langley with the spectro-bolometer on the infra-red spectrum of sunlight, demonstrated the existence of marked absorption bands, some of which are due to water vapour.
But they could not detect any absorption by water vapour at a pressure of 7 mm.
At the ordinary temperature the dissociation pressure of copper sulphate is less than the pressure of water vapour in the air, and therefore copper sulphate does not effloresce.
The existence of water vapour is clearly shown by photographs of the planet's spectrum taken by Mr. Slipher at the Lowell Observatory in 1908.
The so-called "telluric lines" seen in the solar spectrum, are due to water vapour in the earth's atmosphere.
Thus, he showed that two volumes of hydrogen combine with one volume of oxygen to form two volumes of water vapour; that one volume of nitrogen combines with three volumes of hydrogen to form two volumes of ammonia gas, and so on.
Thus the artificial formation of dew and consequent determination of the dew-point is a recognized method of measuring the pressure, and thence the amount of water vapour in the atmosphere.
Thus, when the dew-point temperature has been determined, the pressure of water vapour in the atmosphere at the time of the deposit is given by reference to a table of saturation pressures of water vapour at different temperatures.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "water vapour" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.
