When there are heavy dews water may be collected by spreading out a blanket with a stick attached to one end, tying a rope to it, dragging it over the grass, and wringing out the water as it accumulates. In some parts of Australia this method is practiced. In traversing the country upon the head waters of Red River during the summer of 1852, we suffered most severely from thirst, having nothing but the acrid and bitter waters from the river, which, issuing from a gypsum formation, was highly charged with salts, and, when taken into the stomach, did not quench thirst in the slightest degree, but, on the contrary, produced a most painful and burning sensation, accompanied with diarrhoea. During the four days that we were compelled to drink this water the thermometer rose to 104 deg. in the shade, and the only relief we found was from bathing in the river. The use of water is a matter of habit, very much within our control, as by practice we may discipline ourselves so as to require but a small amount. Some persons, for example, who place no restraint upon their appetites, will, if they can get it, drink water twenty times a day, while others will not perhaps drink more than once or twice during the same time. I have found a very effectual preventive to thirst by drinking a large quantity of water before breakfast, and, on feeling thirsty on the march, chewing a small green twig or leaf. Water taken from stagnant pools, charged with putrid vegetable matter and animalculae, would be very likely to generate fevers and dysenteries if taken into the stomach without purification. It should therefore be thoroughly boiled, and all the scum removed from the surface as it rises; this clarifies it, and by mixing powdered charcoal with it the disinfecting process is perfected. Water may also be purified by placing a piece of alum in the end of a stick that has been split, and stirring it around in a bucket of water. Charcoal and the leaves of the prickly pear are also used for the same purpose. I have recently seen a compact and portable filter, made of charcoal, which clarifies the water very effectually, and draws it off on the siphon principle. It can be obtained at 85 West Street, New York, for one dollar and a half. Water may be partially filtered in a muddy pond by taking a barrel and boring the lower half full of holes, then filling it up with grass or moss above the upper holes, after which it is placed in the pond with the top above the surface. The water filters through the grass or moss, and rises in the barrel to a level with the pond. Travelers frequently drink muddy water by placing a cloth or handkerchief over the mouth of a cup to catch the larger particles of dirt and animalculae.