DEVONIAN 



DIAMYL 



lain, by heating it to a high temperature: 

 when, on cooling slowly, it becomes white 

 and opaque. 



Devonian strata, (De-vo'ni-an). [Devonshire.] 

 Marine and fresh-water beds, corresponding 

 to Old Bed Sandstone, found in S. of Eng- 

 land, between the Silurian and Coal forma- 

 tions, having numerous fossil remains of fish. 

 The term Devonian is sometimes reserved for 

 marine strata. The term Old Ked Sandstone 

 is sometimes reserved for fresh-water strata. 

 Upper Devonian=Pilto. 



Devourer-beetle=Broscus. 



Dew, (dfi). [Deaw, the A.-S. name.] Small 

 globules of water, deposited chiefly at night 

 time upon solid bodies that are colder than 

 the air; hoar frost is frozen dew. D. berry: 

 a variety of Rubus fruticosus, or blackberry. 

 D, claw: a rudimentary fifth digit, found in 

 Newfoundland puppies. 



Dewlap, (da'lap). [Dew, q.v.; lap, to lick.] 

 Folds of loose skin hanging from the neck in 

 oxen. 



Dew-worm=Lob-worm=:Earth-worm , q. v. 



Dextral, (deks'tral). [Dexter, the Latiu word.] 

 =Right-handed. 



Dextrin, (deks'trin)=Dextrine. [L. dexter, 

 right-handed.]=C 6 H 10 O5: a transparent brit- 

 tle gum, which is obtained fr<?m starch, and 

 causes right-handed rotation in polarised light; 

 one of the amyloids. Also caUed British gum. 



Dextrogyre, (deks-tr5-ji're). [L. dexter, right- 

 handed; gyrus, a circle. ]=Polarization to the 

 right. 



Dextrorsal, (deks-tror'sal). [L. dexter, right- 

 handed.]=Bight-handed: used of a spiral, or 

 of rotation. 



Dextrose, (deks'tros). [L. dexter, to the right 

 hand.]=C 6 H 12 6 .H 2 O=Starchsugar=Grape 

 sugar; obtained from dried fruits and starch; 

 a compound of starch and water. 



Dhourra, (do'ra) = Helena Arundinaceus : a 

 grass plant, very easily cultivated, which 

 yields a very large return. 



Di, (di). [Gk. dis, twice.] A prefix meaning 

 two or twice. ., 



Diabetic sugar, (di-a-be'tik). [Gk. dlabaino, 

 I go through.]=C6Hi2O(j.2H2O: grape sugar 

 found in urine in the disease called diabetes, 

 and causing right-handed rotation in polar- 

 ised light, i. y/ v 



Diadelphia,*(dI-a-delfi-a).'^"[Gk. dis, twice; 

 adelphos, brother.] A sub-division of plants 

 in the Linnaean system, containing those, 

 chiefly leguminous, which have the stamens 

 in two bundles. 



Diadelphous, (di-a-del'fus). [Diadelphia, q.v.] 

 Having the stamens in two bundles. 



Diadem lemur. A lemur belonging to Indris- 



inse, q.v. 



Diagonal, (dl-ag'o-nal). '' [Gk. dia, through; 

 gonia, comer.] A straight 

 line joining the opposite 

 angles of a parallelogram. 



Diagram, (di'a-gram). [Gk. 

 diagrapho, I describe.] A Diagonal. 



drawing in outline. J). of a flower: a hori- 

 zontal section, showing the respective posi- 

 tions of its various parts as seen from above. 



Dial telegraphs, by which signals are expressed 

 by the movements of a hand upon a dial- 

 plate. 



Diallage, (di'al-aj). [Gk. diallasso, I ex- 

 change.] A compound of silica with lime 

 and magnesia, a variety of pyroxene, fre- 

 quently found in volcanic rocks; named from 

 its colour not being always the same. 



Diallogite, (di-al'16-jit). [Diallage, q.v.} A 

 metallic mineral, crystallising in hexagons, 

 chiefly carbonate of magnesia; belongs to the 

 manganese group. 



Di-allyl, (di'aMil). [Di and allyl, q.v.]= 

 (C^f^in : the hydrocarbon of the allylic 

 series ; a volatile liquid, the vapour of which 

 is combustible. 



Dialuric acid, (di-a-lu'rik) = C4H 4 N 2 O 4 : an 

 acid obtained from alloxan; also called hy- 

 dride of alloxan. 



Dialypetalaj, (dl-al-i-pet'a-le). [Gk. dialysis, 

 separation; petal, q.v.] Brongniart's term 

 for a division of Exogens belonging to An- 

 giospermeee, having flowers in which the 

 petals, if there be any, are free from each 

 other. 



Dialyser, (di-a-li'zer). [Gk. dialysis, loosen- 

 ing.] A vessel closed below by a porous mem- 

 brane, through which dialysis takes place. 



Dialysis, (di-al'i-sis). [Gk. dialysis, loosen- 

 ing.] The separation of crystalloid and col- 

 loid bodies by means of a membrane, through 

 which they pass in iinequal degrees. 



Diamagnetism, (di-a-mag'net-izm). [Gk. dia, 

 through; Magnetism, q.v.] = Repulsion of 

 substances, such as bismuth and antimony, 

 by magnets. 



Diameter, (dl-am'e-ter). [Diametros, the Greek 

 word.] A straight line drawn 

 through the centre of a circle to 

 meet the circumference on each/ 

 side: generally a straight linei 

 drawn through the middle of a 

 figure, and so dividing it into 

 equal parts. Diameter. 



Diamides, (di'a-midz). [Gk. dis, twice ; Amide, 

 q.v.] Compounds formed by two, four, or six 

 atoms of hydrogen in two molecules of am- 

 monia, being replaced by a dibasic electro- 

 negative radicle. Primary D., in which two 

 atoms are so replaced. Secondary D., in 

 which four atoms are so replaced; these 

 include the imides and ureides. Tertiary 

 D., in which all the hydrogen is replaced. 



Diammonias, (di-am-mo'ni-az). [Gk. dis, twice; 

 Ammonia, <?.?;.]=Diatomic bases=Diamines: 

 bases formed from diatomic alcohols by re- 

 placing two, four, or six atoms of hydrogen 

 by a dyad hydrocarbon radicle. 



Diamond, (di'a-mond). [Diamant, the French 

 word.] Pure crystalline carbon, 

 the hardest substance known, 

 possessing great lustre owing to 

 its great refracting power. 



Diamyl, (di'a-mil). [Gk. dis, 

 twice; Amyl, Q.v.]=(C 5 H 11 )2= 

 Amyl=Amylamylide: a colour- Diamond, 

 less aromatic liquid; a hydro- (Brilliant.) 

 carbon, obtained during the distillation of 

 coal; the molecular formula of amyl. 



