FLINT. 



FLOUR. 



dung, where its young are hatched, and pass 

 through their transformations. The larvae and 

 pupae do not differ much in appearance from 

 those of common house-flies." 



Meat-flies. "It is found all summer about 

 slaughter-houses, butchers' stalls, and pantries, 

 which it frequents for the purpose of laying its 

 eggs on meat. The eggs are commonly called 

 fly-blows ; they hatch in .two or three hours 

 after they are laid, and the maggots produced I 

 from them come to their growth in three or 

 four days, after which they creep away into 

 some dark crevice, or burrow in the ground, 

 if they can get at it, turn to egg-shaped pupoe, 

 and come out as flies, in a few days more ; or 

 they remain unchanged through the winter, if 

 they have been hatched late in the summer. 

 A smaller fly, of a brilliant blue-green colour, 

 with black legs, also lays its eggs on meat, but 

 more often on dead animals in the fields. It 

 seems hardly to differ from the Musca (Lucilia) 

 Ceesar of Europe. The house-fly of this coun- 

 try has been supposed to be the same as the 

 European Musca domestica; but I cannot satisfy 

 myself on this point for the want of specimens 

 from Europe. It is possible that our sharp- 

 biting stable-flies, the meat-flies, and the house- 

 fly, may really be distinct species from those 

 which are found in Europe." 



House-fly. The American house-fly is the 

 Musca harpyia,or harpy-fly of Dr. Harris's Cata- 

 logue. It begins to appear in houses in July, be- 

 comes exceedingly abundant in September, and 

 does not disappear till killed by cold weather. It 

 is probable that, like the domestic fly of Europe, 

 it lays its eggs in dung, in which its larvae live, 

 and pass through their changes of form. The 

 Americans are accused of carelessness in re- 

 gard to flies, and apparently with some reason. 

 But, if these filthy, dung-bred creatures swarm 

 in some houses, covering every article of food 

 by day, and absolutely blackening the walls by 

 night, in others comparatively few are found ; 

 for the tidy house-keeper takes care not to 

 leave food of any kind standing about, unco- 

 vered, to entice them in, and makes a business 

 of driving out the intruders at least once a 

 day. If a plateful of strong green tea, well 

 sweetened, be placed in an outer apartment 

 accessible to flies, they will taste of it, and be 

 killed thereby, as surely as by the most ap- 

 proved fly-poison. In the first volume of The 

 Transactions of the Entomological Society of Lon- 

 don, Mr. Spence gives an account of a mode 

 of excluding flies from apartments, which has 

 been tried with complete success in England. 

 It consists of netting, made of fine worsted or 

 thread, in large meshes, or of threads alone, 

 half of an inch or more apart, stretched across 

 the windows. It appears that the flies will not 

 attempt to pass through the meshes, or between 

 the threads, into a room which is lighted only 

 on one side ; but if there are windows on 

 another side of the room, they will then fly 

 through; such windows should therefore be 

 darkened with shutters or thick curtains. 

 (Harris.') 



FLINT. Common flints are nearly pure 



silica, which is composed of a metal (silicium) 



and oxygen gas; it is tasteless, insoluble in 



water, or fluoric acid, and dissolvable only by 



488 



means of potash. Flints usually occur in 

 irregular nodules in chalk. They abound 

 considerably in some sorts of soils. Sand is 

 commonly chiefly composed of flint. A spe- 

 cimen of flint analyzed by M. Klaproth con- 

 tained 



Farts. 



Silica 98 



Alumina ..... 0'25 

 Oxide of iron .... 0'25 

 Water 1-50 



100 



Flint, when exposed to intense heat, becomes 

 opaque, and forms a kind of porcelain. This 

 was well illustrated in the fire in the Tower of 

 London, in 1841. The flints of the muskets 

 were all thus changed. See EARTHS. 



FLOAT. A raft of timber bound together 

 to be conveyed by water. It also signifies 

 locally to turn water upon meadow land for 

 improving it; and likewise to pare off the sur- 

 face or sward. 



FLOATING OF MEADOWS. See IRRI- 

 GATION. 



FLOUR (Span, flor ; It. fiore ; Fr. fleur de 

 farnie). The meal of wheat corn or other grain, 

 separated from the husk or bran, and finally 

 ground and sifted. There are in England three 

 qualities of flour, denominated first, seconds, and 

 thirds, of which the first is the purest. (See 

 BREAD.) The proportion of flour which a 

 bushel of grain affords greatly varies. A 

 bushel of Essex wheat, Winchester measure-, 

 weighs upon an average about 60 Ibs., which, 

 when ground, will yield (exclusive of the loss 

 incurred by the grinding and drying) 45$ Ibs. 

 of the flour called seconds, which alone is used 

 for baking throughout the greater part of Eng- 

 land, and affords the most wholesome, though 

 not the whitest bread. Besides the seconds, 

 such a bushel of wheat yields 13 Ibs. of pollard 

 and bran ; the total loss in grinding seldom 

 exceeds one pound and a half. 



The corn of the different species of grain, 

 produces, when ripe, nearly the following 

 quantities of meal or household flour and bread 

 per bushel: viz. 



Wheat if weighing 60 Ibs., of flour 48 Ibs. of bread 64 Ibs. 

 Rye 54 42 56 



Barley 49 37* 50 



Oats 40 22i 30 



The flour of wheat which is cut before it is 

 quite ripe is whiter than that which is allowed 

 to come to maturity, and bears a higher price in 

 the markets. The grain which is intended for 

 the miller should, therefore, be reaped before 

 it has reached its utmost growth; but that 

 which is meant for seed should be allowed to 

 stand until the last moment at which it can be 

 cut with safety. The corn is ground into 

 meal of various degrees of fineness, and a 

 bushel of 60 Ibs. generally yields, when dressed, 

 about the following quantities, viz. 



Fine flour 

 Household flour 

 Pollards - 

 Bran ... 



- 22L 



A bushel of wheat, therefore, averages 48 Ibs. 

 of both kinds of flour of the sort called "se- 

 conds," and a sack of marketable flour should 

 by law weigh 280 Ibs. These products must, 



