Calithump

IMG:content-0464.png:[graphic] on river banks. The leaves of all are bipinnate, the leaflets varying much in size and number. In one section the leaves have one to four pairs of pinnæ, with few but large leaflets (one to eight inches long), the ultimate ones always the largest; while in another there are many pairs of pinnæ, the leaflets scarcely half an inch long, linear in form and almost numberle . The flowers are usually borne on stalked globose heads, but sometimes in terminal racemes; the corollas small and hidden by the very numerous long filaments of the stamens, which are almost always of a beautiful red color. From this latter circumstance the genus is named Calliandra , signifying "beautiful stamened." It differs from all allied genera in the valves of its compre ed pod rolling backwards in a remarkable manner from apex to base when the seeds are ripe. Fig . 2756. CALLIANDRA TWEEDIL. Calochortus, ( kāl - o - chōr'tūs .) ( Bot . ) A gen. of beautiful bulbous plants, Ord. Liliacese . They have tunicated bulbs, and produce rigid ensiform leaves, and an erect scape supporting a few large showy flowers which are racemosely arranged and remain open for several days. The perianth is deciduous, six-leaved, the three outer or calycine divisions linear and beardle , the three inner petaloid, very much larger and broader than the outer, and bearded on the inside; the flowers, therefore, appear to consist of three large spreading petals, and three narrow sepals. There are six stamens adherent to the base of the perianth, and a three-celled ovary crowned by three subse ile stigmas. The few known species, which are found in Mexico, California, and N.W. America, are all plants of gorgeous beauty, but found to be exceedingly difficult of cultivation. Calochortus venustus is one of the handsomest; it grows about two feet high, and produces large flowers, upwards of three inches acro , with narrow green sepals, and broad roundish wedge-shaped petals which form a cup, and are white above, yellowish towards the base, each of them marked with a wedge-shaped deep crimson stain, terminating in a yellow spot, and above this, in the same line, with a deep red spot bordered with yellow, and a spot of lighter red. Fig . 2757. CALOCHORTUS VENUSTUS. Calorescence, ( kah -lores-sens.) [Fr., from Lat. cal or , heat.] ( Phys .) A term introduced by Profe or Tyndall to designate the transmutation of invisible heat-rays into rays of higher refrangibility, that is, into visible rays. Sir William Herschel discovered the fact, that, beyond the red end of the spectrum, there are invisible heat-rays of great intensity. Suppose a sunbeam is caused to pa through a prism, it is split up into rays of different refrangibility, occurring in the order of violet, indigo, blue, green, yellow, orange, red. This experiment constitutes the so called decomposition of white light, and was first made by Newton. Sir W. Herschel, in pa ing a delicate thermometer through the various portions of the spectrum, found that the temperature gradually rose as it pa ed from the violet to the red end, and the red was found to be the hottest portion. He then moved his thermometer into darkne beyond the red, and found an indication of a considerable amount of heat, in fact, a greater amount than had been found in any part of the visible spectrum. It was thus clearly demonstrated that invisible heat-rays accompany the visible light-rays emitted from the sun. The relationship of the heat spectrum to the light spectrum has been determined by Sir W. Herschel and Pro fe or Müller in the case of the solar spectrum, and by Profe or Tyndall in the case of the spectrum of the electric light. The last-mentioned physicist, in attempting to sift the luminous from the calorific rays of the total radiation from the voltaic arc, tried various substances with a view of finding something which should cut off the whole of the light, and allow the heat to pa . He ultimately decided on using a solution of iodine in bi-sulphide of carbon. The bi-sulphide alone was found to absorb only 5-2 per cent. of the heat-rays pa ing through it; and when iodine was added until the solution was perfectly opaque, the absorption of heat was scarcely increased, while the absorption of light was complete. When a beam of light from the sun, or from the electric lamp, was pa ed through a layer of this opaque solution, and concentrated by a lens, the dark heat-rays were brought to a focus, at which intense calorific effects were manifested; black paper, was instantly set on fire, gunpowder and guncotton were exploded, and thin plates of tin and zinc fused. At the dark invisible focus, carbon was brought to incandescence, and caused to burn vividly, - blackened silver-leaf was brought to a red heat, copper was melted, and platinized platinum rendered incandescent. It was nece ary in these experiments to blacken bright surfaces exposed to the focus of dark heat, otherwise the reflection of heat would have been so considerable that the substance would not have absorbed a sufficient amount to raise it to red heat. Here, by ultra-red invisible heat-rays, Tyndall raised metals to incandescence -that is, they emitted light of their own-and we perceive at once that this is virtually a transformation of invisible rays into visible rays. The ultra-red rays po e low refrangibility; the vibrations which produce them are long, and move too slowly to produce in us the sensation of vision; they fall as dark invisible heat on the platinum, or other metal raised to incandescence, and they leave it as light; the slow vibrations have become quicker, the long waves have become shorter, the refrangibility has been raised. This change of heat-rays into light-rays is calorescence. The transmutation is complete. The invisible heat-rays are not converted into light of one kind, for when a piece of white hot platinum is examined by means of a prism, a complete spectrum is obtained-in a word, the he a trays of low refrangibility are converted into light-rays of all refrangibilities. A detailed account of the experiments in connection with this subject will be found in Tyndall's Heat Considered as a Mode of Motion , and in his various memoirs in the Philosophical Transactions. Calor'ic Engine. ( Mech .) A form of heat engine, invented by the distinguished Swedish engineer, John Eric on, in which hot air is the acting substance. Air engines, in their principal working parts, closely resem{ble steam engines, the heated air being introduced into a cylinder in which works a tightly-fitting piston, which is forced to move up and down by the expansive pre ure of the heated air, and transfers its motion to machinery by means of a connecting rod and revolving shaft in the usual manner. The air is heated in a furnace, is introduced below the piston, lifts it, and then escapes into the atmosphere. As the power of the engine depends on utilization of the heat of the air, means are taken to preserve as much as po ible of this heat and prevent its escape into the atmosphere. This is done by means of a "regenerator," or chamber filled with screens of wire gauze, through which the hot air is made to pa in its escape from the cylinder, and which take up much of its heat, which they give up again to the fresh air pa ing through them, inward to the furnace. Caloric engines have the advantages of needing no boilers and not being subject to explosion. Their power, however, is comparatively small, and they are only useful for light machinery. Calorie ( kal - lor - e ' ). [Same deriv. as calorescence.] A term used by the French to designate the unit of heat which they adopt. It is the amount of heat nece ary to raise 1 kilogramme (2-2046215 lbs. avoirdupois) of water one degree centigrade in temperature; strictly from 0° to 1o C. A calorie, when converted into mechanical force, is competent to raise a weight of 1 kilogramme to a height of 425 metres (one metre is equal to 3-2808992 feet), and conversely the fall of 1 kilogramme through a space of 425 metres represents, as heat, one calorie. Calorimetry, ( kāl - o -rim'e-tre.) [Lat. cal or , and Gr. metron, measure.] ( Phys .) The thermometer indicates relative, not absolute amounts of heat; it shows the condition of a body in regard to sensible heat, that is, the temperature of the body, but the real amount of heat from 32° to 33° F.; or the amount nece ary to raise 1 lb. of water from 0 to 1o C.; or again, the French unit or calorie, viz., the amount of heat nece ary to raise 1 kilogramme of water from 0° to 1o C. The absolute quantity of heat absorbed or given out by a substance in pa ing through a given range of temperature compared with that absorbed or given out by water under similar conditions is called its specific heat ; we have here to examine the various methods by which specific heat is determined, in other words, the various proce es of calorimetry. Three principal methods are employed for the determination of specific heat. In the first the heat is measured by the amount of ice which it melts; in the second, known as the method of mix tures, bodies of different temperatures are mixed with water, and the heat calculated from that of the mixture; and in the third, or method of cooling , the heat is determined by noticing the time which a body requires to cool. -1. Determination of Specific Heat by Fusion of Ice. The first and rudest form of calorimeter was a block of ice containing a cavity covered by a lid of ice; a known weight of the substance to be examined, at a known temperature, was placed in the cavity, and when it had cooled down to the temperature of the surrounding ice, it was removed, and the cavity was wiped dry by a weighed cloth, which, on being again weighed, obviously gave the weight of water resulting from the fusion of the ice by the substance introduced. This calorimeter was employed by Black and Wilke; it was greatly improved by Lavoisier and Laplace, and used by them for the determination of the specific heat of a number of substances. The instrument in its improved form is IMG:content-0465.jpg:[blocks in formation] known as the Ice Calorimeter (Fig. 2758, in which i gives a perspective view of it, and 2 represents a section), and consists of three concentric ve els, in the innermost of which (M) the substance whose specific heat is to be determined is placed, the surrounding ve el (A) is filled with ice, and is provided with a tap for drawing off the water, while the outermost ve el (B) also contains ice, and is for the purpose of preventing the melting of ice in the intermediate ve el, by other means than the heat of the warm substance in the central ve el. The chief objection to this instrument is, that the actual quantity of water resulting from the fusion of the ice, cannot be actually determined, because some remains in contact with the unmelted ice. 2. Method of Mixtures. According to this method, a known weight of the substance whose specific heat is to be determined, is heated to a known temperature, and is then immersed in a known weight of cold water, the precise temperature of which is noted. The temperature which results from the immersion of the warm body, when both it and the water po e the same temperature, is then observed, and the specific heat of the immersed substance calculated therefrom.-3. Method of Cooling. When equal volumes of different substances at the same temperature are allowed to cool under precisely similar conditions, the rate of cooling is found to vary considerably. It has been found that equal weights of different bodies cool through the same number of degrees of temperature in times which are directly as their mined by thermometrical means. Calorimetry is that branch of the science of heat which treats of the absolute measurement of heat, and the instruments employed for such determinations are called Calorimeters. The existence of two such terms as Thermometry and Calorimetry, in the same science, is undoubtedly unfortunate, because as far as their derivation is concerned, they might both apply to the same cla es of phenomena. The thermometer was invented and named before calorimetry had been even thought of, and when the latter came to be practised, it was thought that no term which did not expre the measurement of heat, could with any justice be applied to determinations of absolute quantities of heat, and the only convenient term remaining was calorimetry. It would be preferable to call the thermometer a thermoscope , and the calorimeter a thermometer, but it is unlikely that the latter term, from its comparative antiquity, will ever cease to be used in its present form. For the exact measurement of heat three forms of thermal unit are employed: to wit, the amount of heat nece ary to raise 1 lb. of water such determinations. It has been chiefly employed by Dulong and Petit, and by Regnault. Cal'verly, CHARLES STUART, the prince of modern English parodists, was born Dec. 22, 1831. His education was received at Harrow, Baliol College (Oxford), and Christ College (Cambridge), where he graduated as second cla ic in 1856. He was called to the bar in London in 1865, but a fall on the ice closed what gave every promise of being a brilliant career in the law. He became famous as a humorous poet, his works comprising Verses and Translations and Fly Leaves , the former published in 1862, the latter in 1872. Died Feb. 17, 1884.