DROP 



108 



DTTBA 



Drop-wort, (drop'wurt)=Spirsea filipendula : 

 an herb belonging to Bosacese. Water D.= 

 jEnanthe : an herb belonging to Umbelliferse. 

 D. of water : a colourless transparent topaz. 



Drosera, (dros'e-ra). [Gk. droseros, dewy.]= 

 Sundew : an herb the type of Droseraceae. 



Droseraceae, (dros-er-a'se-e). [Drosera, q.v.] 

 = Sundews : marshy herbs, sometimes 

 poisonous, with small violet-like flowers, 

 belonging to Berberales. 



Drummond-light=0xyhydrogen light : a yel- 

 low light produced by heating a ball of lime 

 in hydrogen which is burning in. oxygen ; 

 also called lime-light. 



Drupacese, ( droo-pa'se-e ). [Drupe, q.v. ~\= 

 Almond - worts : trees and shrubs, with 

 regular flowers, belonging to Rosales; also 

 called Amygdalesa. 



Drupe, (droop). [L. drupa, an over-ripe 

 olive.] A fruit such as the cherry or 

 peach, with a succulent substance sur- 

 rounding a hard centre, and having a 

 leathery covering. 



Drusy minerals, (droo'zi). [Gk. drosos, dew- 

 drop. 1 Those that are sprinkled with 

 minute crystals of the same or another kind. 



Dry fruits. Fruits having a thin pericarp 

 and little or no j nice. v. Fruits. 



Dry-rot. 1. Decomposition : the carbon and 

 hydrogen are changed into carbonic anhy- 

 dride and water by the absorption of oxygen. 

 2. Fungi, such as Merulius lacrymans and 

 Polyporus hybridus, which grow upon wood 

 and animals. 



Dry-piles. A number of discs of leather, 

 paper, &c., coated on one side with an 

 electro-negative, and on the other with an 

 electro - positive substance, which form a 

 Voltaic battery of limited power. 



Dryas, (dri'as). [Gk. dry as, wood-nymph.] 

 A shrub belonging to Rosacese. 



Drying oils, such as linseed, walnut, and hemp 

 oils, <fec., which absorb oxygen and solidify, 

 for which reason they are used in painting. 



Dryobalanops, (drl-o-bal'a-nops). [Gk. drys, 

 oak ; balanos, acorn.] A tree belonging to 

 Dipteracese.] D. ca7?ip^ora=Camphor tree. 



Dryopithecus, (dri-o-pi-the'kus). [Gk. drys, 

 tree ; pithekos, ape.] An ape living amongst 

 trees. 



Dualistic system of chemical combination, in 

 which salts are considered as formed by the 

 union of two binary compounds ; thus sul- 

 phate of potassium is formed by the com- 

 bination of sulphuric acid and oxide of 

 potassium, each of which is a binary com- 

 pound. 



Dubescq's electrical lamp, An apparatus by 

 which the electric light is made continuous 

 and steady. 



Dubhe. A star=aUrs8e Majoris. 



Duchess. A term used for roofing slates 24 

 inches by 16 inches. 



Duck, (duk).=Anas : an aquatic bird belong- 

 ing to Natatores. 



Duck-bill, ( duk'bil ) = Ornithorhynchus = 

 Water mole : an aquatic animal ; also called 

 Platypus, having a mouth resembling a 

 duck's bill; also called Duck-mole. 



Dugong. 



Ducks Anatidse, q.v. 



Duckweed, ( duk'wed ) = Lemna : a small 



aquatic plant, consisting of floating fronds, 



with very minute flowers, belonging to 



Pistiacesw. The lowest known form of 



phanerogamous plants. 



Duckweeds=Pistiacese: plants of which duck- 

 weed is the type. 

 Duct, (dukt)=A tube. 

 Ductility, (duk-til'i-ti). Used of the tenacity 



of some metals, by which they can be drawn 



into wires, often very fine. 

 Dudley limestone = We nlock limestone: a 



sub-division of the Wenlock formation in 



Upper Silurian strata. 

 Dufrenite. A mineral containing iron and 



magnesium. 

 Dugong, (du'gong). [The Malayan name.]= 



Halicore = Sea-cow : 



a cetacean animal,, 



found in the Indian" 



Ocean, feeding on 



vegetables. I 



Duhanel's graphic 



method of marking 



the .vibrations of a 



sounding body by 



traces on a black- 

 ened sheet of paper. 

 Dulcamara, (dul-ka-ma'ra). [L. dulcis, sweet ; 



amarus, bitter. ] = Bitter-sweet = Woody 



nightshade^Solanum dulcamara. 

 Dulcite, (dul'sit). [L. dulcis, sweet.]=C 6 H ]4 



Og : a saccharine substance obtained from 



milk sugar. 

 Dulong and Petit's law. That specific heats 



of simple bodies are inversely as their 



atomic weights. 

 Dulse, (duls). [The Scotch word.]-Rhodo- 



menia palmata : an edible sea-weed, common 



in Scotland. 

 Dumb - bell cluster of stars = Hour - glass 



nebula, in Vulpecula. 

 Dumb cane = DifFenbachia seguiana, a plant, 



which, when eaten, causes the tongue to swell 



so as practically to cause dumbness. 

 Dumortier's classification of plants : 

 Staminacia 



Gorticalia. 

 Decorticalia. 

 Pollinacia 



Capsellia. 

 Ecapsellia. 

 Fluidacia 



Soligrania. 



Plurigrania. 



Dunes, (dunz). [Celtic dun, a hill.] Low 



sand hills on the coast. 

 Duodenum, (du-o-de'num. ) [L. duodeni, 



twelve inches.] The portion of the intestine 



communicating with the stomach, into which 



the food passes from the stomach, and in 



which it is converted from chyme into chyle 



by the biliary and pancreati secretions. 

 Duplicate ratio. The ratio of the squares of 



two numbers is the duplicate ratio of the 



numbers. Ex.: the duplicate ratio of 2 and 



3 is the ratio of 4 to 9. 

 Dura-mater, (du'ra-ma'ter.) [L. durus, hard : 



