B LE 



BL U 



the Rhamnus catharticus, or Buck- 

 thorn, mixed with gum arabic and lime 

 water. 



BLANCHING. Etiolation. The pro- 

 cess of whitening the leaves and stems 

 of plants, by excluding the light, and 

 thus preventing the development of their 

 natural properties. 



BLANK VERSE. Verse without 

 rhyme or the consonance of final syl- 

 lables! 



BLASTE'MA {/SXaa-Tdvta, to bud). A 

 Greek term applied to the rudimental 

 mass of an organ in the state of forma- 

 tion ; it is said to consist of fluid, nucle- 

 ated cells, and granules which spontane- 

 ously change into cells and into nuclei of 

 cells. Botanical writers apply the term 

 to the thallus of lichens; according to 

 Mirbel, the blastema comprises the ra- 

 dicle, plumule, and caulicle of the em- 

 bryo. 



BLASTOCA'RPOUS (/3\ao-T6r, a shoot, 

 KapTTOf, fruit). A term applied, in Bo- 

 tany, to those plants in which germina- 

 tion takes place within the fruit before 

 it fells, as in the mangrove. 



BLA'STUS (ySXao-TOf, a shoot). A term 

 sometimes applied to the plumule of 

 grasses. With the same idea, Richard 

 considers the scutelliform cotyledon of 

 these plants to be a particular modifica- 

 tion of the radicle, and calls it hypo- 

 blastus ; the anterior occasional cotyledon 

 he views as a peculiar appendage, and 

 names it epiblastus ; the radicle is a pro- 

 tuberance of the caulicle, and termed 

 radiculoda. Finally, to embryos of this 

 description he gives the general designa- 

 tion of macropodal. Dr. Lindley observes 

 that in these ideas Richard was wrong, 

 as is now well known. 



BLA'TTID^. A family of Ortho- 

 pterous insects, named from the genus 

 blatta, a familiar species of which is 

 known under the vernacular term cock- 

 roach. 



BLEACHING. The chemical process 

 of whitening linen or woollen stuffs. 

 1. Linen is bleached, by the old process, 

 by exposure to air and moisture ; by the 

 new process, by means of chlorine or 

 solution of chloride of lime. 2. Woollen 

 stuffs are bleached by soap and water, 

 which is called the Natural Method ; or 

 by exposure to the vapour of sulphur, 

 which is commonly called bleaching by the 

 flower, or bleaching of Paris, because this 

 method is employed in that city more 

 than elsewhere, 



BLEACHING POWDER. Chloride 

 54 



of lime, prepared by exposing hydrate 

 of lime gradually to chlorine gas. This 

 compound is obtained in solution by 

 transmitting a stream of chlorine gas 

 through hydrate of lime suspended in 

 water, and the solution is tnen called 

 bleaching liquid, or oxymuriatic alkaline 

 water. 



BLENDE. A term signifying a mine- 

 ral which contains no ore, particularly 

 applied to the native sulphuret of zinc, 

 but extended by mineralogists to other 

 substances, as manganese-blende, anti- 

 mony-blende, ruby-blende, &c, 



BLETTING. A term adapted by Dr. 

 Lindley to denote that peculiar bruised 

 appearance in some fruits, called blessi 

 by the French, for which we have no 

 equivalent English expression. 



BLIGHT, A popular name for various 

 diseases of plants. These diseases are 

 probably owing to arrest of the natu- 

 ral functions of plants by circumstances 

 depending on temperature and the con- 

 ditions of the atmosphere. 



BLO'EDITE. A massive translucent 

 salt, found at Ischel in Upper Austria, 

 together with prismatic gypsum. 



BLOODSTONE. Hccmaiites. A green 

 agate coloured by chlorite, with nume- 

 rous red spots like drops of blood ; called 

 also heliotrope and oriental jasper. 



BLOW-PIPE. A small conical tube, 

 bent at one end, so as to be easily intro- 

 duced into the flame of a candle or lamp, 

 for the purpose of directing a stream of 

 flame, by blowing through it, upon any 

 object which is to be heated. 



Oxy-hydrogen Blow-pipe. An apparatus 

 for producing intense heat, by supplying 

 a stream of hydrogen with pure oxygen, 

 so that the two gases issue together in 

 the form of a jet from the nozzle of the 

 blow-pipe. 



BLUE COMPOUNDS. 1. Prussian 

 or Berlin blue is the sesquiferricyanide 

 of iron ; basic Prussian blue is a com- 

 pound of Prussian blue and peroxide of 

 iron. 2. Saxon blue is a sulphate of in- 

 dijro, or a solution of indigo in concen- 

 trated sulphuric acid. 3. Blue verditer is 

 an impure carbonate of copper ; blue cop' 

 per ore is the finely crystallized subcar< 

 bonate of copper. 4. TurnbulVs blue is 

 the ferricyanide of iron, precipitated on 

 adding red prussiate of potash to a proto- 

 salt of iron. 5. Blue vitriol, copperas, 

 or blue stone, is the sulphate of copper, 

 prepared by roasting and oxidating the 

 sulphuret of copper. 6. Blue John is a 

 technical name for fluor or Derbyshire 



