212 Oil jo t Chronomelers.

ltourr,. Min, At 4 19,.-S8 cubic feet of water were evaporated; and ~ cwt. of

coke consumed. At 4 ,3~--41~ cubic feet of. water were evaporated, with a con-

sumption of £5~ lbs. of coke. From which it appears, that" only 6 lbs. of coke per cubic foot of

water per hour was consumed, and the evaporation of- a cubic tbot of water per hour being generally considered the measure of a horse power, the conclusion is, tliat the boiler was a 40 horse boiler, and that the quantity of fuel requisite to work it is g¼ cwt. per hour, the expense of' which is l ~ d . and as the consumption diminishes after the tirst hour~ the expense of fuel will probably not exceed Is. per hour for the tbrty horse boiler. ,

(Signed,) ALE, KANDi,:R NIMMO, C. E.

Oiljbr Chronometer~'.--By Mr. HENRY W:LK~SSON, Oj" Pall Mall. From the "I'ransactlons of the Society of Art's,

"I'r~: best olive oil in its recent state possesses that peculiar bland tlavour whicli tits it for the table, and which appears to arise princi- pally fi'om lhe quantity of mucilage and water, either held in solu. tion, or mechanically mixed with it. By keeping one or two years in jars, a considerable portion of the mucilage and wate~r subsides, which renders such oil not only cheaper, but better qualitied for yielding a greater 1)roportion of pure oil than that which is recently, expressed f'o u the t?uit. Two or three gallons .skimmed f,'om thee surfiice of a large jar that has remained at rest for twelve months or upwards~ is preferable to any succeeding portion from the same jar~ and may be considered the cream of the oil. Having procured good oil in the first instance, put about one gallon into a cast iron vessel capable of holding two gallons; place it over a slow cleat, tire, keeping a thermometer suspended in it; and when the temperature rises to £e0 °, check the heat, never allowing it to exceed gS0 °, nor descend below 21e °, for one hour, by which time the whole of the water and acetic acid will be evapm'ated: the oil is then exposed to a temperature ot" ,30 ° to .36 ° for two or three days, (consequently winter is preti:rable fbr the preparation, as avoiding the trouble and expense of producing artificial cold; by this operation a considerable portion is congealed; and, while in this state, pour the whole on a muslin filter, to allow the fluid portion to run throuozh; the solid, when redissolved, may be used for common purposes. ~ Lastly, the fluid portion must be tiltered once or more through newly prepared animal charcoal~ grossly nowdered, or rather broken a n d laced 0~ tm)utous paper m a w~re frame, within a funnel; by which operaliou rancidity, (if any be presenh) is entircly removed, and the oil is ren- dered perfectly bright and colourless.

1-1~Nrt~ ~ W~L::I~m~