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ARTEMIS Arte of the Wool Merchants; connected with it is a corn-warehouse decorated with statues of the saints, contributed by the arte or guilds of the city, and executed by the best artists of the time.

We have spoken of the term art as covering all human activity. We have thus far avoided any special reference to that form of human activity which consists in the contemplation and analysis of nature— the subject which we call science. Nevertheless, since science strictly speaking, does not aim to produce things, but only to ascertain truths, it is clearly to be seen that it can be included only in the broadest interpretation of the term we are defining. If we can show what part of the field of human activity belongs to science, we may, by establishing its boundaries, find put just what is the field of art.

With what material does science deal? Our premise was that science deals with existing fact; all facts in nature fall within the scope of science. What is it that science does with these facts? Science observes, records, and in so far as possible explains these facts, shows their relations, one to another, and makes deductions from them. Now, with what does art deal? Art, since it adds to those things which nature has provided, deals with the production or attainment of ends, first assuming the desirability of such ends. Architecture, the art of building, for instance, assumes the need of houses and sets about producing them. Architecture calls in science with its knowledge of the stone, wood and clay which nature has provided and its knowledge of the effects of the elements upon such stone, wood and clay. Having obtained this knowledge from science, architecture acts upon it. To sum up the functions of art and science: "Science is the knowing, art is the doing. Art evolves, science involves."

It is thus seen that art cannot go on without science. Neither can science advance its investigations without the aid of art—that is to say, human activity— in carrying on its experiments and building its hypotheses. Science has been described as in the indicative mood, expressing itself by means of the declarative sentence: "Two and two are four." Art, then, is in the imperative: "Produce four." While science deals with the fundamentals by which ends are to be attained, art deals with the ends themselves, and with the attaining of them. .

Artemis. See.

Ar'tery, the name of the tubular vessels that convey blood from the heart. There are two sets of arteries: (1) The great aorta, springing from the left ventricle of the heart and reaching by numerous subdivisions and branches all the tissues of the body. (2) The pulmonary artery, springing from the right ventricle of the heart and branching through the lungs. The former is the systemic, the latter the pulmonary system. The pulmonary artery, of course, carries venous blood. The arteries are elastic, and, when filled with blood, are stretched and exert a steady pressure on that fluid. This causes them to force most of the blood on into the veins after death, and led the ancient anatomists to believe that the arteries were air tubes and the veins only blood vessels. The arteries and veins are connected by capillaries. The aorta was named by Aristotle.

Artesian (är-tē ' zhan) Wells are borings straight down into the ground through which water rises above the surface of the ground. The possibility of getting water in this way depends upon the rock formation at a place. There is more or less water in all rocks. Rocks which are sandy and easily broken up part with a greater or less portion of the water they receive. For example, a cubic yard of pure sea-sand can hold about one third its bulk of water. It would part with nearly the whole of this into a well sunk in it and regularly pumped from. Chalk, which is composed of fine particles closely pressed together, holds as large a proportion of water; but from the power of what is called capillary attraction—the same power that lifts the sap in trees—little water would drain into a well sunk in such a rock. Where porous layers of rock are found resting on a layer which is impervious to water and covered by another layer also impervious, the water in the middle layer is held imprisoned. Where these three layers run i across a valley and up a hill on each side, they will be exposed to the air at the top. The falling rain is carried down the middle layer, and gathers at the bottom of the valley, and in time the whole porous layer becomes water logged, and the water at the center is under strong pressure. Now, if a bore is made at the bottom of the valley into the water logged layer, the pressure will force the water above the surface. The most famous artesian well is that at Grenelle near Paris, which was bored in 1833—1841. and whose water is brought from a depth of 1,798 feet. It yields 516½ gallons of water a minute, which is forced thirty-two feet above the surface. The Chinese and Egyptians knew about artesian wells, and they have been bored in the Sahara desert. There are many artesian wells in the United States, where they are utilized for supplying cities, towns, villages and farms with water. Artevelde (ar'ta-velt) Jacob Van, a Flemish leader of the people in the i4th century, was a brewer in Ghent. His wealth, eloquence and talents made him