100

FUEL.

FLOOKAN. The name given by the Cornish miners to a vein of clay-stone, oft ennearly vertical.

FLOOR-CLOTH MANUFACTURE has become of late years a very 1^. branch of trade. The cloth is a strong somewhat open canvass, woven of flax '* rlt slittle hemp, and from 6 to 8 yards wide, being manufactured in appropriate 1°° .chiefly at Dundee. A piece of this canvass from 60 to 100 feet in length, is secU j a .tight in an upright open frame of oaken bars, in which position it receives the ^° un . )U tlion coats of paint, 2 or 3 in number, first on the black side, and then on the front;it previously is brushed over with glue-size, and rubbed smooth with pumice-sto®The foundation paint made with linseed oil and ochre, or any cheap coloring eia ’is too thick to be applied by the brush, and is therefore spread evenly by a long n? r j l6trowel, held in the right hand, from a patch of it laid on just before with a brush inleft hand of the workman. Each foundation coat of the front surface is smoothed^pumice whenever it is hard enough to bear the operation. When both sides are ,

painted cloth is detached from the frame, coiled round a roller, in this state tran |* (T e ar edto the proper printing-room, where it is spread flat on a table, and variously “gand colored devices are given to it by wooden blocks, exactly as in the block-p rinof calicoes, and in the wood-printing of books. The blocks of the floor-cloth m“ nlure are formed of two layers of white deal and one of pear-tree timber, placed ^

their grain crossing one another alternately. There is of course a block for eachin the pattern, and in each block those parts are cut away that correspond to th ^pressions given by the others; a practice now well understood in the printing oi t'\ S)more colors by the press. The faces of the blocks are so indented with fi ne it

that they do not take up the paint in a heavy daub from the flat cushion on

the nat cushion uu . j. e r

is spread with a brush, but in minute dots, so as to lay on the paint (somewhat tn . jlter .than that of the house-painter) in a congeries of little dots or teeth, with minute resticks between. Applied in this way, the various pigments lie more evenly, are ^sightly, and dry much sooner than if the prominent part of the block which taK ^ tothe color were a smooth surface. The best kinds of floor-cloth require fromthree months for their production. ,

FODDER, a weight of 21 cwt., by which lead is sold in the north of England-FUEL. On the measurement of heat, and the qualities of different kinds o^ nI made an elaborate series of experiments, a few years ago, of which the followingoutline’ s for

The first and most celebrated, though probably not the most accurate apparmeasuring the quantity of heat transferable from a hotter to a colder body, f tincalorimeter of Lavoisier and Laplace. It consisted of three concentric cylinder^plate, placed at certain distances asunder; the two outer interstitial spaces heWs en t.with ice, while the innermost cylinder received the hot body, the subject °f eX P. ce ; n it,The quantity of water discharged from the middle space by the melting of th e 1 .]j n der.served to measure the quantity of heat given out by the body in the central )_ ce 0 fA simpler and better instrument on this principle would be a hollow cylindei oproper thickness, into whose interior the hot body would be introduced, an ^ j iea twould indicate by the quantity of water found melted within it the quanti >absorbed by the ice. In this case, the errors occasioned by the retention ° f t rTomd wthe fragments of ice packed into the cylmdric cell of the tin calorimeter, a boy e

avoided. One pound of water at 172° F., introduced into the hollow cylm ^ vT jU

described, will melt exactly one pound of ice; and one pound of oil heated tomelt half a pound. , ern ti® eS

The method of refrigeration, contrived at first by Meyer, has been in m° ^ a t twobrought to great perfection by Dulong and Petit. It rests on the princip ua ntitJsurfaces of like size, and of equal radiating force, lose in like times the sa v essel ot

of heat when they are at the same temperature. Suppose for example, tna dll-

polished silver, of small size, and very thin in the metal, is successively 111 j eTa tionferent pulverized substances, and that it is allowed to cool from the same a iw»)’ stemperature ; the quantities of heat lost in the first instant of cooling j 9 doubJ e

equal to each other; aud if for one of the substances, the velocity c0 ? a jf’wh en jtSof that for another, we may conclude that its capacity for heat is one i ^’^perntu 1 " 6weight is the same ; since by losing the same quantity of heat, it sinks m

double the number of degrees.

hot

body which becomp^oo'^' t! “ s method, two bodies are always employed, “ a jj

the caloric which goes oufof thef d b ° dy -’ which becoraes 1,ot > “““" e SupP ase

for exam nip t w, 1 the , fo ™er is expended in heating the latter. ° " „ t

32° * 9 ‘ V m *5 ^ C a P° un(1 of quicksilver at 212° F., into a pound of flC .

quires a eom,t!! 1 r r W]1! , C ° oi and . th . e water heat, till the mixture by stirring.H^ould liavp nn If tins temperature was 122°, the water and

tual capacities, since the same quantity of heat would produce JU