LAT 



LAX 



LARYNGOTOMY. The opera- 

 tion of making an opening into the 

 larynx ; this is sometimes necessary 

 in eases of choking or severe inflam- 

 mation, where the opening of the 

 larynx, along which air passes, is 

 closed. 



LARYNX. The upper part of the 

 windpipe, formed of cartilage, and ly- 

 ing at the root of the tongue. 



LAST. A quantity, varying in dif- 

 ferent countries, and with respect to 

 various articles. The lollowing quan- 

 tities generally make a last : 12 doz- 

 en of hides or skins ; 12 barrels of 

 meal ; lOV quarters of cole seed ; 10 

 quarters of corn or rape seed (in some 

 parts of England 21 quarters of corn 

 go to a last) ; 12 sacks of wool ; 1700 

 pounds of feathers or flax. 4000 

 pounds is often tlie amount of a last. 



LATENT HEAT. Heat sup- 

 posed to be present in all bodies, and 

 on which their form depends ; it can- 

 not be felt, but, by a change in the 

 form, is given out, and becomes sen- 

 sible or free heat. Vapours and gas- 

 es contain most, next fluids, and last 

 solids ; so that, by the abstraction of 

 heat, vapours are condensed, fluids 

 freeze, and, by the reverse, solids be- 

 come fluid or gaseous. 



LATERITIOUS (from later, a 

 brick). A deposite of a reddish colour 

 from urine, &c. 



LATEX. The milky or elaborated 

 juices of plants : it circulates in a pe- 

 culiar arrangement of tubes called the 

 lalicifcrous vessels, which anasta- 

 mose over the plant. 



LATH. A thin slip of wood, one 

 fourth or three eighths of an inch 

 thick, used in plastering, slating, &c. 



LATHE. A machine for revolving 

 pieces of wood, metal, &c., which are 

 cut with different tools while rotating. 



LATH FLOATED AND SET 

 FAIR. In building, three-coat plas- 

 terer's work, in which the first is 

 called pricking up, the second float- 

 ing, the third, or finishmg, is done 

 with tine stuff. 



LATH LAID AND SET, In 

 building, two-coated plasterer's work, 

 except that the first is called laying, 

 and IS executed w-ithout scratchmg, 



unless with a broom. When used on 

 walls, this sort of work is generally 

 coloured ; when on ceilings, it is 

 white. 



LATHYRUS. A genus of hand- 

 some climbing, leguminous plants, 

 much cultivated for ornament. 



LATICIFEROUS VESSELS. 

 Milk vessels ; they carry the latex. 



LAUDANUM. Opium dissolved 

 in alcohol, tincture of opium. 



LAITREL. Shrubs, or small trees, 

 of the genus Laurus ; several are ev- 

 ergreen : they yield aromatic resins 

 and oils. 



LAURINE. A fatty, acrid sub- 

 stance, found in the berries of the 

 common laurel (Laurus communis). 



LAVA. The molten mineral mat- 

 ter which has flowed from volcanoes ; 

 it is very porous. 



LAYER. A sea-weed (Porphrjra 

 laciniata and vulgaris), eaten as a del- 

 icacy when boiled ; sometimes green 

 laver (Ulva laiissima) is substituted. 



LAVENDER. Lavemiula spica. It 

 grows on a poor, light soil, is propa- 

 gated by slips and cuttings of the 

 year's shoots ; these are set in May, 

 six inches apart, in a shady border, 

 and transferred by October to the 

 permanent beds, about two feet apart. 

 The ground is stirred in spring, and 

 the flowers gathered early in July ; 

 the beds, with a little care, last a 

 long time. The flowers are distilled 

 for their rich perfume, which is the 

 principal ingredient oi eaudc Cologne. 



LAWN. Ground covered with the 

 smaller perennial grasses, kept short 

 by mowing, and generally situated in 

 front of a house or mansion. Lawns, 

 when once established, require only 

 to be kept neat by the ordinary rou- 

 tine of rolling, mowing, and sweep- 

 ing, except keeping the surface per- 

 fectly even, by making up small hol- 

 lows with screened mould early in 

 spring. When lawns become worn 

 out, a top-dressing of any finely-divi- 

 ded manure will refresh them ; leach- 

 ed ashes are particularly useful, and, 

 at the same time, an additional quan- 

 titv of grass seed may be sown. 



LAXATIVE. A gently-purging 

 medicine. 



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