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RES 



object. This is a distinctive character of 

 very considerable value in some minerals, 

 not depending on any accidental circum- 

 stances, but on the nature of the mine- 

 ral. Double refraction is exhibited most 

 strikingly in Iceland spar. 



REFRIGERATED. (from refrigero, Lat.) 

 Cooled. 



REFRIGERA'TION. (refrigeration, Fr.) The 

 act of cooling down ; the state of being 

 cooled. 



It is the opinion of some geologists 

 that the whole of this planet was formerly 

 in an incandescent state, and that the 

 process of gradual refrigeration has been 

 constantly proceeding; that the crust of 

 the earth has cooled down to its present 

 temperature, but that the centre of the 

 earth is still a molten mass. Professor 

 Whewel, speaking of Fourier's arguments 

 on the subject, says, " it results from 

 Fourier's analysis that at a depth of 

 twelve or eighteen miles the earth may 

 be actually incandescent, and yet that the 

 effect of this fervent mass upon the tem- 

 perature at the surface may be a scarcely 

 perceptible fraction of a degree. The 

 slowness with which any heating or cool- 

 frg effect would take place through a 

 solid crust is much greater than might be 

 supposed. If the earth below twelve 

 leagues depth were replaced by a globe 

 of a temperature five hundred times 

 greater than that of boiling water, 200,000 

 years would be required to increase the 

 temperature of the surface one degree." 



REGENERATION, (regeneration, Fr. rige- 

 nerazione, It. regeneratio, Lat.) Repro- 

 duction. The property which some ani- 

 mals possess of reproducing parts which 

 have been destroyed. 



RELi'ciuLdB. (Lat.) Remnants ; remains of 

 the dead. To understand rightly, says 

 Prof. Phillips, the daily accumulating 

 stores of organic reliquiae, requires more 

 than a slight knowledge of existing na- 

 ture, more even than an acquaintance 

 with the animal and vegetable forms. 



RE'NAL. (renalis, Lat, from ren, a kid- 

 ney.) Pertaining to the kidneys. 



RE'NIFORM. (from ren, a kidney, and/br- 

 ma, form, Lat.) Kidney- shaped. 



RENU'LINA. A genus of flat, sulcated, 

 reniform, many-chambered, microscopic 

 foraminiferous shells, with linear cham- 

 bers adapted to the curves of the shells ; 

 the last being the longest. 



RE'PTILE. (reptilis, Lat. reptile, Fr. rettile, 

 It.) A vertebrated, cold-blooded, animal. 

 The body covered with a shell, or with 

 scales, or entirely naked. Possessing 

 neither hair, mammae, feathers, nor ra- 

 diated fins ; breathing through the mouth 

 and nose by means of lungs ; oviparous, 

 but never hatching its eggs, and amphi- 



bious. The oldest formations in which* 

 any reptiles have been found are those 

 connected with the magnesian limestone 

 formation. 



REPTI'LIA. Reptiles form the third class 

 of vertebrated animals, and it is sub- 

 divided into four orders, namely, Chelo- 

 nia, or tortoises, Sauria, or lizards, Ophi- 

 dia, or serpents, and Batrachia, or frogs. 

 Of these four orders, the Chelonians and 

 Batrachians are partly aquatic, partly 

 terrestrial ; the Saurians and Ophidians 

 are principally tenants of the land. 



REPU'LSION. (repulsion, Fr.) That pro- 

 perty possessed by bodies which causes 

 their particles to recede from one another, 

 or to avoid coming in contact. In air 

 and in liquids, the most perfect freedom 

 of motion of the parts among each other 

 subsists, and from this, and other consi- 

 derations, it has been concluded that the 

 several parts do not touch, but are kept 

 asunder at determinate distances from 

 each other, by the constant action of the 

 two forces of attraction and repulsion, 

 which are supposed to balance and coun- 

 teract each other. Herschel. 



RE'SIN. (resina, Lat. resine, Fr.) Called 

 also rosin. A yellowish-white coloured 

 substance, which exudes from many trees, 

 more particularly the different species of 

 fir. It is somewhat transparent, is hard 

 and brittle, of a disagreeable taste, and 

 may be collected in considerable quanti- 

 ties. Resin may be distinguished from 

 other substances by the following pro- 

 perties. It is more or less concrete, and 

 possesses a certain degree of transparency. 

 Its taste is sometimes hot and disagree- 

 able, but not unfrequently it is tasteless, 

 or nearly so. Colour generally between 

 pale yellow and brown. Specific gravity 

 from 1-0 to 1'3. It is electric and a non- 

 conductor of electricity. When heated it 

 readily melts ; and if the heat be much 

 increased it is volatilized, and burns with 

 a white flame and strong odour, producing 

 a great quantity of smoke. It is insoluble 

 in water, and by this may be distinguished 

 as well as separated from gum. It is 

 soluble in alcohol, ether, and in the vola- 

 tile oils. The number of resins is very 

 great, as there is scarcely a plant which 

 does not contain some kind of resin. 



RESINI'FEROUS. (from resina, resin, and 

 fero, to produce, Lat.) Yielding resin. 



RE'SINOUS. Resembling resin ; containing 

 resin ; possessing the properties of resin. 



RESPIRA'TION. (respiratio, Lat. respira- 

 tion, Fr. respirazione, It.) The function 

 of breathing ; the act of inhaling air into 

 and exhaling it from the lungs. Respi- 

 ration consists of two parts, inspiration, 

 which, in a healthy condition, takes place 

 about twenty-six times in a minute, thir- 



