RESINS                                                        1602                                           RESPIRATION

those who fell in field or hospital or have since died; to stand by each other while living; and to bury those who answer the final call as the years go by. The organization was first suggested and planned by Dr. B. F. Stephenson of Springfield, 111. The first post was organized early in 1866, and on July 12 of that year a meeting of representative soldiers from all parts of the state was held at Springfield, where they were mustered in and given authority to organize posts throughout the state. The organization grew rapidly and extended to other states. The posts in each state constitute a department, and the organization in 1906 had 6,055 posts, with a membership of 229,932. The losses by death in the preceding year were 9,205. The motto of the order is Fraternity, Charity and Loyalty. The badge of the Grand Army consists of an eagle and a star, connected by a ribbon representing the flag. A bronze button is also worn as an every-day insignia of the order. The order is strictly non-political, and none but honorably discharged soldiers can become members. There are frequent campfires, reunions and banquets, and once each year a grand, national encampment is held. At these meetings greetings are exchanged, memories are revived, the old songs of the war are sung again and the unwritten history of the war is recalled. Under the auspices of the order large sums are every year expended in charity. Hundreds of soldiers' and sailors' monuments have been erected, orphans' homes have been built and endowed in many states, and a helping hand has been given to thousands of old soldiers and soldiers' widows and orphans. The membership is now rapidly reduced each year by death.

Res'ins, a class of natural vegetable products, closely allied to the essential oils and in most cases obtained from the plants which yield them mixed with oil. Resins are divided into hard, soft and gum resins. Hard resins are solid and brittle, and contain little or no oil. Such are copal, lac, mastic, jalap etc. Soft resins can be molded by the hand, and some are sticky and semifluid. These are called balsams. They are the solutions of hard resins in essential oils, or are admixtures of the two. Turpentine, storax and the balsams of Tolu, Peru and Canada are examples. Gum resins are the milky juices of certain plants made solid by exposure to the air. Resins are widely diffused throughout the vegetable kingdom, and are much used in medicine and in the mechanic arts. They are generally obtained by making incisions in the wood from which they are obtained, although it is sometimes necessary to use boiling alcohol to extract them from the wood. The common resin or rosin of commerce exudes from several species of pine, and is used in the prepara-

tion of ointments and plasters and for various other purposes.

Resonance (rz'-năns), in physics the process by which one body sets in vibration another body having the same period of vibration. When one attempts to ring a large church-bell, he soon learns that he must pull the rope at certain definite intervals if he wishes to ring with ease. A row-boat moored in quiet water can, without difficulty, be set rocking if one throw his weight, first on one side then on the other, at correct intervals. If two pendulums of the same period be mounted upon one common frame, and then one pendulum be set in vibration while the second is at rest, the second pendulum soon "picks up" a vibration of considerable amplitude from the first pendulum. These are instances of resonance, taken from mechanics. In acoustics and electricity there also are many illustrations. A tuning-fork held over a tall jar partially filled with water will have its sound much reinforced when the column of air in the jar above the water is capable of vibrating in the same period as the tuning-fork. The sounding-box of the guitar and violin are in resonance with the strings and enable them to give out energy at a more rapid rate. Electrical resonance is frequently employed in wireless telegraphy. For a complete theory of resonance see Donkin's Acoustics.

Res'pira'tion (in plants) is the process by which most plants set free in their bodies the energy required for doing the work necessary to maintain life and form new parts. It essentially is identical with the respiration of animals. It consists of several separate but related processes : ( 1 ) the absorption of oxygen and its union with the protoplasm or with foods by the action of the protoplasm; (2) the decomposition of this unstable substance, resulting finally in the formation of carbon dioxide and water; (3) ridding the body of these waste products. The oxygen is absorbed directly from the water or air by smaller plants, but in the larger it is distributed to the internal tissues by a system of air passages (see Aeration). Through a reverse process the carbon dioxide is got rid of. The chemical details of respiration are not known. It even is uncertain whether it is the living protoplasm or the foods that are oxidized. Neither is it known how the energy is used nor in what form it is set free. Some of it appears as heat, making the body warmer than the surrounding air. But this heat is so quickly lost that it can only be observed when dissipation of it is hindered. In this the plant is like a cold-blooded animal. On account of the carbon dioxide excreted, the plant loses weight, unless supplied with food; thus, if a seed germinate in darkness, after a few weeks the plantlet may have less than half the dry weight of the seed from which it grew.