S82 



SCIENCE OF AGRICULTURE. 



Tart IL 



2553. The furze-bruiser {fig. 263.) is an in- 

 genious and most useful machine where furze is 

 either grown or found naturally. The shoots are 

 bruised and cut into short lengths by hammers 

 which operate like those in the mills for hammering 

 iron. When the material is not sufficiently bruised, 

 it is afterwards passed between rollers. 



2554. The bone-breaking machine (fig. 264.) 

 consists of two rollers grooved and indented, and 

 with pinions on their ends, by which they may be 

 moved either by animals, water, or steam power. 

 The surfaces of the rollers are filled with indent- 

 ations and strong teeth, v/hich penetrate and break 

 the bones to pieces. This is accomplished by 

 employing separate cast-iron wheels placed side by side upon an axis, to compose the 

 rollers ; the wheels have coarse teeth similar to thosj of a saw or ratchet wheel ; each 



wheel of the lower roller is an inch thick ; and 

 they are placed at distances of an inch and a half 

 asunder, having circles of hard wood or iron 

 placed between them, which are two inches less 

 in diameter. The bones should be supplied rather 

 gradually to the machine at first, to avoid choking 

 it, and the rollers should then be adjusted to a 

 considerable distance asunder ; but when the bones 

 have once passed through in this way, the rollers 

 are screwed closer by screws placed for that pur- 

 pose, and the fragments ground a second time. 

 The pinions (a a) must have deep cogs to enable 

 them to take deep hold of each other, when the 

 rollers are set only half an inch distant to grind 

 fine, and without the cogs being liable to slip 

 when the centres are separated so far as to leave 

 a space of one inch or one inch and a quarter 

 between the rollers, for the passage of the large 

 bones the first time. The rollers will act most 

 effectually, if the different wheels are fixed upon their axles in such a position that 

 the teeth will not correspond or form lines parallel to the axes, and then no piece of 

 bone can escape without being broken by some of the teeth. The bones which have 

 passed through the rollers slide down an inclined board, and collect at the bottom in a 



large heap. When all the stock of bones are thus coarsely broken, a labourer takes them 

 up in a shovel and throws them again to the hopper to be ground a second time. (Supp. 

 to Encyc. Brit. Art. Agr. ) In a modification of this machine to be impelled by horse 

 power, manufactured by Weir of London [fig. 265.), the bones, after passing through 

 the rollers, are conducted by the hopper (a) into a revolving screen (6), which is driven 

 by a bevel wheel [c) working into a pinion on the screen shaft (rf, e). 



2555. The oil-cake bruiser is composed of two rollers ground and toothed like the 

 rollers of the bone-mill, but it is on a smaller scale so as to be worked by one 

 man. The object is to bruise the oil-cake to a dust or powder. Below the rollers 

 is a screen for separating the grosser pieces which are set apart for feeding cattle, and 



