DEFLECTION 



96 



DENDRERPETON 



deflagration or brilliant combustion. Hare's 

 D.=Hare*3 battery, which produces great 

 heat. 



Deflection of magnet. The change of direc- 

 tion in a freely suspended magnetised needle 

 when any external force, sucli as a Voltaic 

 current, counteracts, wholly or partially, 

 the magnetic attraction of the earth. 



Deglutition, (deg-lu-tish'un). [L. de. down; 

 glutio, I swallow.] Tha swallowing of food 

 previous to digestion. 



Degree. The circumference of every circle is 

 divided into 3GO equal parts, called degrees, 



written 360, so that one degree is -3 iff * 

 the circle. The radius of a circle in moving 

 half way round the circle moves through 

 180, and through one degree if it move 

 through irio of the whole. D. of latitude^. 

 69 statute miles, or 60 nautical miles. D. 

 of longitude: varies from at the poles to 

 jTBT of the equator. D. of thermometer 

 Fahrenheit D. : TTD- of the distance between 

 freezing and boiling points of water. Centi- 

 grade D. : T77J- of the distance between 

 freezing and boiling points of water. Rea- 

 mur D.: -y-jj of the distance between freezing 

 and boiling points of water. 

 Dehiscence, (de-his'ens). [L. dehisco, I open.] 

 The opening of any en- 

 closure, as of a seed-vessel 

 when ripe. 



Dehiscent. Opens when ripe. 

 Dehydration, ( de - hid - ra'- 

 shun). [L. de, from ; Gk. 

 hydor, water. ] The remo val 

 of water from any compound 

 containing it as a consti- 

 tuent. Dehiscent 

 Deinosauria, (dl-no-saw'ri-a). [Gk. deinns, 

 terrible; saura, lizard.] An extinct order 

 of reptiles=Dinosauria, q.v. 

 Deka, (dek'a). [The Greek word.]=10 times. 

 Dekametre = 10 metres ; Dekagram = 10 

 grams ; Dekastere=10 steres ; Dekalitre=10 

 litres. 



Dekametre, (dek-a-m5'tr). [Gk. deka, ten; 

 Metre, ?.v.]=Kette of N. Germany=Ten 

 metres=393'7079 inches. 

 Delambre, A crater in the moon, 26 miles in 



diameter. 



De la Rive's floating battery. A small gal- 

 vanic cell fastened on a cork so as to float 

 freely on water. 



Deleuil's air-pump. In which, to avoid 

 friction and heat, the piston is not in con- 

 tact with the cylinder in which it works, 

 the very small space between being filled 

 with air which adheres to the piston. 

 Delfim, (del'fim)=:Coryphaena Nortoniana : a 



fish of Madeira. 



Deliquescent, (de-lik-wes'ent). [L. de, from ; 

 liquesco, I become fluid.] Absorbing mois- 

 ture, and in consequence becoming liquid 

 or soft. 



Delisle's method of observing a transit, in 

 which the apparent times of ingress and 

 egress are noted at different places on the 



earth's surface, from which the orbit may 

 be deduced. 



De Lorme system. In construction of bows, 

 or supports for roofs or bridges, in which a 

 number of pieces of timber is formed into a 

 bow or arch. 



Delphinidae, (del-fin'i-de). [Gk. delphin, dol- 

 phin.] A division of Cetaceae, including 

 dolphins, porpoises, &c. 



Delphinium, ( del-fin'i-um ). [Gk. delphin, 

 dolphm.]=Larkspur: an herb, common in 

 temperate climates, belonging to Ranun- 

 culacese, named from the shape of its flowers. 



Delphinus, ( del'fi n-us ). [Gk. delphin, dol- 

 phin.] l.=Dolphin : an animal resembling 

 the whale, but having a smaller head, the 

 type of Delphinidse. 2.=The Dolphin : a 

 small constellation of stars, all of small 

 magnitude, in the northern heavens. 



Delta, (delta). [A The fourth letter of the 

 Greek alphabet.] Alluvial land, usually 

 triangular in shape, deposited at the mouth 

 of a large river, formed of the soil brought 

 down by the river. 

 D. moths = Deltoides : 

 named from shape of 

 wings, belonging to 

 Lepidoptera. 



Deltohedron, ( del - to - 

 hed'ron). [Delta, q.v.; 

 Gk. hedra, base.] A 

 solid figure the surface 

 of which is formed by 

 twenty-four deltoids. 



Deltoid, (del'toid). [Delta, 

 form.] 1. A four-sided 

 figure, formed of two 

 unequal isosceles tri- 

 angles on different sides 

 of a common base. 2. 

 A triangular muscle 

 covering the shoulder 

 joint. 



Delvauxite. A resin- 

 like mineral, chiefly 

 phosphate of iron. 



Dematiei = Black-moulds : 

 fungi, belonging to Hyphomycetes, which 

 have a cortex or bark, and a dingy colour. 



Demilune, (dem-i-luu'). [P. demi, half ; lune, 

 moon.] In a fortification, an outwork, usu- 

 ally crescent-shaped. 



Demodex, ( dem'o-deks ). [Gk. demos, fat ; 

 dex, worm.] A microscopic arachnid found 

 in human fat. 



Demoiselle, ( dem-waw-sel' ). [The French 

 name.] 1. Numidian crane : a bird belong- 

 ing to Grallatjres. 2. A dragon fly=-Calop- 

 teryx virgo. 



Demoivre's. theorems. 1. That of any group 

 of eighty-six persons born at one time, one, 

 and one only, will die every year. 2. In 

 Trigonometry: (sin. ^-fcos.. 0*J~\n = ( s ia.. 

 n g + cos. n0-\/-l). 



Demulcents, (de-mul'sents). [L. demulceo, 

 I soothe.] Anything of a soothing or soften- 

 ing nature, used especially,of medicals used 

 to allay irritation. 



Dendrerpeton, ( den-drer'pe-ton ). [Gk. den- 



Deltoid. 



