K Y D 



K Y D 



I . K. calyana. Roxb. t. 2 1 5.— Outer calyx four-leaved, 

 longer than the corolla.— Native of the banks of rivulets, in 

 Coromandcl and Hindooftan, flowering in the cool fealon. 

 A tm, with long-iblked, roundifh, mealy, flightly thrce- 

 lobed Ifavfs. Floivtrs fmall, white, in terminal panicles. 



2. Y^. fralerna. Roxb. t. 216. — Outer calyx fix-leaved, 

 fhorter than the corolla. — Native of the Circar mountains, 

 flowering in the rainy feafon. A larger tree than the fore- 

 going. Floivers more confpicuous. Leaves whiter under- 

 neath. 



L. 



LABORATORY. Woulfe's Apparatus, Plate V. 

 Chemijlry. 



LAC, in Coinage. See Lack and Rupee. 



LACK, in Geography, 1. 2, r. 1 1 65. 



LACKAWANACT, a townfliip of Mercer county, 

 in Pennfylvania, having 379 inhabitants. 



LACTATES, in Chemijlry. See Lactic Add. 



LACTIC Acid. The defcription of this acid has been 

 omitted, we fliall therefore introduce a brief account of it 

 here. 



The laftic acid was firft obtained by Scheele from four 

 whey. He confidered it as analogous to the acetic acid. 

 Bouillon Lagrange afterwards inftituted a feries of experi- 

 ments upon it, from which he drew the conclufion that it 

 is merely acetic acid, contaminated with fome faline and 

 animal matter. Four years afterwards, Thenard advanced 

 a fimilar opinion. Both thefe chemifts, however, had 

 obtained the acid which they examined by diftillation, 

 though Scheele had exprefsly ilatcd that laftic acid, when 

 diftilled, was converted into acetic acid. The cxiilence of 

 laftic acid, therefore, was by no means difproved by their 

 experiments. Soon afterwards, Berzelius took up the fub- 

 jeft, and in an elaborate fet of experiments proved that 

 Scheele's original opinion was correft, and thus fully 

 eftablidied the peculiar nature of laftic acid. 



Berzelius obtained the laftic acid by the following com- 

 plicated procefs. The extraft obtained by evaporating 

 whey to drynefs was difltilved in alcohol, and mixed with 

 alcohol holding y,th of its weight of concentrated fulphuric 

 acid in folution, till there was an exccfs of fulphuric acid pre- 

 fent. Sulphate of potalh was precipitated. To get rid of the 

 other acids, it was digefted over carbonate of lead till the 

 liquid acquired a fweetiib talle. By this means, the fulphuric 

 acid, the phofphoric acid, and moll of the muriatic acid, were 

 feparated ; but the laftic acid forming a foluble compound 

 ■with lead remained in folution. A current of fulphuretted 

 hydrogen gas being paflcd through the liquid threw down 

 the lead. The liquid was digefted over quick-lime till all the 

 animal matter was feparated. It now contained only laftic 

 acid, muriatic acid, and lime. A portion of it was freed 

 from lime by means of oxalic acid. This portion was then 

 fatnrated with carbonate of filver ; by means of this folu- 

 tion, the remainder of the liquid was freed from muriatic 

 acid. Finally, the lime was thrown down by means of 

 oxalic acid, fo that nothing remained but laftic acid dif- 



folved in water. To get rid of a fmall portion of oxalate 

 of lime which it held in folution, it was evaporated to 

 drynefs, and rediffolved in water. 



Laftic acid thus obtained lias a brownifh-yellow colour, 

 and a ftiarp four talle, which is much weakened by diluting 

 the acid with water. While cold it has no fmell, but 

 when heated it acquires a iliarp lour odour, not unlike that 

 of fublimed oxalic acid. It does not cryftalhze, but when 

 evaporated to drynefs forms a fmooth varnifh, which gra- 

 dually attrafts moifture from the air. It diffolves readily 

 in alcohol. When heated it boils, emits a four fmell, and 

 leaves a bulky charcoal, not eafily burnt. When diltilled 

 it gives out empyreumatic oil, water, acetic acid, carbonic 

 acid, and inflammable gas. 



LaBates. — All the laftates are more or lefs foluble in 

 water, and hardly any of them can be made to cryftallizc. 

 The laBate of potajh and lactate of foda form a light 

 yellow tranfparent gummy mafs, which cannot be eaiily 

 made hard. The ladate of ammonia has fome tendency to 

 cryllallize. It forms a gummy mafs, which acquires in the 

 air an excefs of acidity. When heated, moll of the ammonia 

 is driven off. The laBales of barytes, lime, and magnefia, 

 are divided by alcohol into fuperlaBates of thofe earths 

 which are foluble in alcohol, and into fubladates which are 

 infoluble. Tlie metallic laftates do not poflefs remarkable 

 properties. There are three lactates of lead ; the fuper- 

 laQate which does not cryftallize, the laSate whicli exiils in 

 grey cryftaUine grains, and the fuila^ate which is infoluble. 

 The ladate of %'inc cryilaUizes. 



Dr. Thomfon ellimates the weight of the atom of laftic 

 acid from Berzelius's experiments at 57.5. 



Such are the chief properties of laftic acid and its com- 

 pounds. We have entered further into the defcription than 

 we ftiould otherwife have done, on account of the importance 

 of the fub'ieft, — the laftic acid exilling both in a iimple and 

 combined Hate in moll of the animal fluids. See Blood, 

 and Fluids, Animal. 



LACTODORUM, ill Ancient Geography. See Tow- 



CESTER. 



LACTUCARIUM, a name given by Dr. Duncan 

 to the infpiffated juice of the laducafativa, or common lettuce, 

 and which has been found beneficial in various diforders, 

 efpecially confumption, as an anodyne, where opium difagreed 

 and could not be taken. 



LADY-BIRD. See Coccinella. 



LAFOURCHE, in Geography, a county of the territory 



of 



