69-79) the distinctive 2 " The soil of this marsh [east of Palmyra] is so impregnated with salt that a trench or pit sunk in it becomes filled in a short time with concentrated brine, the water of which evaporates in the intense sunshine and leaves an incrustation of excellent salt."
It slowly evaporates, leaving a thin crust of animal and vegetable matter.
==Pharmacology, Toxicology and Therapeutics of Alcohol== Alcohol is of great medicinal value as a solvent, being used to form solutions of alkaloids, resins, volatile oils, iodoform, &c. In strength of about 10% and upwards it is an antiseptic. If applied to the skin it rapidly evaporates, thereby cooling the skin and diminishing the amount of sweat excreted.
The elevation of the boilingpoint is of little practical importance, but the reduction of vapour pressure means that sea-water evaporates more slowly than fresh water, and the more slowly the higher the salinity.
The water of most of the springs and geysers holds silica in solution in considerable quantities, so that as it cools and evaporates it deposits a dazzling white sinter which has covered many square miles of the valleys and contrasts strongly with the dark green of the surrounding forests.
Exposed overnight to a cool dry gentle wind from the north-west, the water evaporates at the expense of its own heat, and the consequent cooling takes place with sufficient rapidity to overbalance the slow influx of heat from above through the cooled dense air or from below through the badly conducting straw.
Liquid at the condenser temperature being introduced into the refrigerator through the regulating valve, a small portion evaporates and reduces the remaining liquid to the temperature T1.
With liquid machines of the compression and absorption system, the rooms are either cooled by means of cold pipes or surfaces placed in them, or by a circulation of air cooled in an apparatus separated from the rooms. The cold pipes may be direct-expansion pipes in which the liquid evaporates, or they may be pipes or walls through which circulates an uncongealable brine previously cooled to the desired temperature.
Applied externally, ether evaporates very rapidly, producing such intense cold as to cause marked local anaesthesia.
But this competition among inventors, whatever the incentive, has not been without benefit, because to-day, by means of very simple improvements in details, such as the addition of circulators and increased area of connexions, what may be taken to be the standard type of multiple-effect evaporator (that is to say, vertical vacuum pans fitted with vertical heating tubes, through which passes the liquor to be treated, and outside of which the steam or vapour circulates) evaporates nearly double the quantity of water per square foot of heating surface per hour which was evaporated by apparatus in use so recently as 1885 - and this without any increase in the steam pressure.