432 



FARMERS' REGISTER. 



[No. r 



we make the following extract, Avhich will be 



found no less curious than useful, and cannot tail 



to interest our readers : 



Feet per second. 



The ordinary rate of a man vvaikincp, - 4 

 Of a gooii horse in hanu'ss, - - 12 

 (Or 2,000 toises (ya ds) in minutes.) 

 Of a reinileer in a f?Iedge, on the ice, 26 



Of an English race-horse, - - 43 

 Of a hare, - - - - - 88 

 Of a man casting a stone with all his 



force, 60* 



Of a good sailing ship, - - - 19 



Of the wind, 82 



Of sound, . - . . - 1,038 

 Of a cannon-shot (24-pounder) - 1,300 

 Of the air which returns into space so 

 divided, 1,300 



From tlie London Meclianics Magazine. 



SOAP FROM FUNTS. 



Mr. Sheridan takes the common blark-f]int, cal- 

 cined, and reduces it to powder by wet-grmding ; 

 then mixes it with the caustic soda leys, or potash 

 leys, and boils it till it attains saponification. The 

 mixture so obtainedt is added to the present soap 

 materials after the latter have been boiled to that 

 state when they have become soap, and are ready 

 to be poured into the li'ames. The mixture, which 

 has a high detergent quality, requires to be well 

 crutched along with the soap materials ; and when 

 thus crutched together, the result is a soap of ex- 

 cellent quality. The mixture becomes intimately 

 incorporated with the soap materials, and may be 

 added in proportion of from 40 to 50 parts of the 

 mixture to 50 of the soap materials. Thus the 

 common silex, which is obtainable at a very low 

 price, takes the place of tallow to the extent near- 

 ly one-half 



From the Rail Road Journal. 

 MANUFACTURE OF COKE. 



Extract from Professor Renwick's ./Ipplication of 

 Chemistry to the Useful Arts. 



Coke bears the same relation to bituminous coal, 

 which charcoal does to wood, and is, like it, ob- 

 tained by distillation at a red heat. Bituminous 

 coal is a compound of carbon, hydrogen, and oxy- 

 gen, in very various proportions. In the variety 

 called caniiel coal, the proportion of hydrogen 

 amounts to 5^- per cent. In the Liverpool coal it 

 is about 3^ per cent.; and in the slaty varieties 



* We believe this calculation to be incorrect. A 

 stone cast with strength of a man's arm would outstrip 

 a hare. 



t The compound here alluded to is a coraiiination of 

 silica (silex) and potassa (potash,) and is frequently 

 called liquor of flints. Silica is a body still pjenerally 

 ranked with the earths, which it resembles in many 



Eoints, but it is, in its chemical relations, an acid, com- 

 inininp; with alkalis, and forming salts, wliich are 

 called silicates. It may be considered a curious fact, if 

 the al)ove statement be correct, that this weak mine- 

 ral acid should be able to take the place of the weak 

 animal or vegetable acids united with alkalis in ordina- 

 ry soapg. 



does not exceed one per cent. The quantity of 

 carbon varies from 75 per cent, in cannel coal, to 

 90 per cent, in that of Newcastle. The propor- 

 tion of oxygen in cannel coal is about twice as 

 great as would suffice to convert the hydrogen into 

 water; in the Newcastle coal about four times as 

 great ; and in the slaty varieties, it but hltle ex- 

 ceeds the proper relaiion. 



Coals may be divided into three varieties: 



1. Tiiose which contain at least tliree per cent, 

 of hydrogen, and, at mosr, as nmch oxygen as 

 will convert half the hydrogen into water. 



2. Coals which contain oxygen in such quanti- 

 ty as to convert two-thirds of the hydrogen into 

 water. 



3; Coals which contain oxygen enough to con- 

 vert the whole of the hydrogen into water. 



The first of these varieties fuses when heated, 

 and the excess of hydroi:;en uniting with a part of 

 the carbon, escapes in the gaseous form ; by the 

 formation and escape of gas, the coke is rendered 

 light and porous. The second variety fuses also, 

 but the quantity of gas formed is not suliicient to 

 render the coke porous; it is therefore compact and 

 massive. 



The third variety does not fuse, and the escape 

 of the vapor of water reduces the mass to the forra 

 of powder. 



Coal of the first class increases in volume when 

 it is coked ; the oiher two varieties yield coke in 

 less volume than the coal employed. In their uses 

 in the arls, the first furnishes the most valuable 

 coke; the last that ofleast value.' 



Coke may be prepared in iron cylinders or re- 

 torts, but this is only done when the volatile pro- 

 ducis are to be collected ; this method will there- 

 fore be described when we treat of the preparation 

 of gas lor illumination. Treated in this way, can- 

 nel coa! yields about fiity jier cent, of coke, and 

 that of Newcastle as mucli as eighty per cent. 



When the distillation is performed at a low 

 temperature, the weight of coke is increased, but 

 its volume and porosity are diminished. It is 

 therelbre advantageous, when the volatile matters 

 are not the princi|)al object, to effect the decompo- 

 sition of the coal bv a sudden and high heat. 



Preparation. — When coal is rich in hydrogen, 

 it may be readily coked in heaps resembling the 

 pits used in preparing charcoal. The coal must 

 be in pieces having not less than three or four 

 inches in each dimension. The heaps are conical, 

 having a base fifteen feet in diameter, and a 

 height of about thirty inches. The heap may he 

 best covered with siraw, on which is laid a layer 

 of moist earth, the siraw being so applied that the 

 earth cannot enter into the s[)aces between the 

 pieces of coal. But as the use of straw is expen- 

 sive, it is more usual to cover the large coal tor 

 about the height of a foot from tlie ground with 

 smaller pieces, and the outside with coal-dust ; 

 the top of the heap is covered with the refuse coke 

 which is left in the form of powder, in handling 

 that obtained in previous operaiions. The heap 

 being finished, a few lighted coals are dropped 

 into an opening of si.x or eight inches in depth lelt 

 in the top ; the space is then filled up with frag- 

 ments of coal, and when the combusiion has lairly 

 commenced, the whole is covered with earth or 

 refuse ccke. The rest of the [)roce6s is much the 

 same as that of preparing charcoal, but is easier, 

 as coal when in mass will not continue to burn al- 



