917 



BARLEY, POT AND PEARL. 



BARLEY, POT AND PEARL. 



019 



Professor Johnston gives the composition of barley-meal as follows : 



Water 14 per cent. 



Gluten 14 



Starch 68 



Fatty matter 2 



Ash 2 



100 



The whole grain, according to Mr. Hereford's analysis, contains 

 15'3 per cent, of gluten and other nitrogenous compounds. Dr. Play 

 fair, in Morton's ' Cyclopaedia of Agriculture,' puts it as follows : 



Nitrogenous substances . . . .13 per cent. 



Starch 56 



Woody fibre 134 



Ash 3J 



Water 14 



100 



A crop of 36 bushels on about 1J tons of straw from each acre, will 

 contain, according to Dr. Playfair's statement, as follows : 



In the Grain. In the Straw. In both. 



Ibs. Ibs. lln. 



Nitrogenous matter . 243 62 305 



Starch and fibre . . 1301 2987 4288 



Ash . . . .66 191 257 



Water . . . . 262 398 660 



1872 3638 



The ash contains the following ingredients : 



Of the Grain. 



Potash . 



Soda . 



Lime . . 



Magnesia 



Iron and loss . 



Phosphoric acid . 



Sulphuric acid 



Silica 



Chloride of sodium 



15-61 

 5-03 

 3-06 

 8-04 

 1-24 



35-68 

 1-22 



28-97 

 0-45 



5510 



Of the Straw. 



22-17 



0-84 



7-59 



3-55 



4-35 (?) 



3-22 



2-61 

 46-30 



9-37 



These are Dr. Playfair's figures : they agree pretty accurately with 

 those of Messrs. Way and Ogsten, as given in the Journal of the 

 English Agricultural Society. The remarkable feature in these 

 analyses, as compared with those of wheat and oats, is the presence of 

 BO large a percentage of magnesia. The quantity of silica in the ash 

 of the grain of barley, is due to the chaff or husk of the floret, which 

 in barley adheres to the grain. The ash of naked barley would more 

 nearly resemble that of other grains. 



In the three years ending with 1858, the quantity of foreign barley 

 imported amounted on an average to 1,398,000 quarters annually. 



BARLEY, POT and PEAEL. Pot-barley is barley of which the 

 outer skin only has been removed ; whereas pearl-barley is the small 

 round kernel which remains after the skin and a considerable portion 

 of the barley have been ground off. 



Both these preparations of barley are made by means of mills con- 

 structed for the purpose, and differ only in the degree of grinding 

 which the grain undergoes. 



There are two kinds of mills for making pot and pearl barley. The 

 mill which was probably the earliest in use, and which is still common 

 in parts of Germany and France, to take off the husk of the barley, is 

 similar to a common flour-mill, having two millstones, of which one is 

 fixed and the other revolves horizontally over it ; but these stones are 

 of less diameters than common millstones, not exceeding three feet 

 each. The upper stone has six grooves, in the form of the fourth part 

 of a circle, cut in the lower surface from the centre to the circum- 

 Fi K . 1. 



ference ; the width and depth of these grooves increase from one inch 

 in the centre to two inches at the circumference (see Jig. I). This 



stone has a perforation in the centre, as a common upper millstone, and 

 revolves on a vertical axis or spindle of iron, the lower point of which 

 moves in a metal cup fixed on an elastic horizontal beam. It is abso- 

 lutely requisite that this axis be perfectly vertical, and the stones 

 accurately horizontal, in order that the upper stone may move parallel 

 to the lower, at such a distance as to rub the grain without crushing it. 

 The mill is fed by a hopper through the central aperture, as in the 

 common com mill. The stones are surrounded by a circular case, 

 leaving a space of from two to three inches between the circumferences. 

 The top or flat part of this case is of wood, and has an aperture corres- 

 ponding with the central aperture of the upper stone ; but the circum- 

 ference consists of thin plates of iron perforated from the outside, by 

 means of a flat punch, with holes, as near each other as possible, making 

 the inside of the case rough, like a nutmeg-grater. A square opening 

 in this case, with a sliding door over it, serves to let out the barley 

 after it has been sufficiently ground. In order to loosen the skin 

 without rendering the substance of the grain too soft, the barley, 

 which is chosen dry and hard, is sprinkled with water on the floor, and 

 turned over two or three times in the course of eight or ten hours : it 

 is then fit to be put into the mill. The upper stone is made to revolve 

 from 200 to 300 times in a minute. The barley, gradually supplied 

 from the hopper, is carried round in the grooves of the upper stone 

 and rubbed on the under without being broken. The centrifugal force 

 and the strong current of air produced by the grooves and the rapid 

 motion, drive the grain, partially ground, against the rough case, and 

 complete the removal of every part of the skin. The rubbed grain is 

 then let out through the square opening, and falls on a sieve, which 

 separates the naked grain from the bran. This is pot-barley. To make 

 pearl-barley, the operation is continued till the required degree of 

 fineness is produced. As the greater part of the finer particles of the 

 barley ground off escape through the holes in the case, it is surrounded 

 by another to collect this meal, or a cloth is fixed all round, which lets 

 it fall gently in a bin below; thus nothing is lost. This meal is 

 excellent food for cattle, pigs, or poultry. The chief objection to mills 

 of this construction is, that they require great nicety in the adjustment 

 of the stones, and are very apt to waste the barley by grinding it 

 unequally, and that, at all events, the larger grains are more ground 

 than the smaller ; but for pearl-barley, which ought to be of a uniform 

 size, this is rather an advantage. But, on the other hand, the process 

 goes on without interruption, and if two or more pairs of stones are 

 placed under each other, the barley may pass from the first into the 

 hopper of a second, and from this into a third, so as to come out of the 

 last of any required degree of fineness. It may be observed, that the 



Fig. e. 



The construction of this machine may be thus briefly described : A, section of 

 the stone turned by the axis D. B, section of the case which turns on the 

 axis D, by means of brass bushes in its centre, c c, a wheel having sixty 

 teeth, or cogs, fixed to the side of the case, o E, a smaller wheel, or 

 pinion, with fifteen teeth, moving the wheel c c ( and fixed on the axis F F, 

 by which the whole is moved, o a, a wheel with sixty teeth, on the axis 

 p F, moving the pinion a H, which has twelve teeth, with the axis D, 

 which carries the stone. 1 1, a fly-wheel, which equalises the motion of the 

 whole. 



principal use of the upper stone and its grooves is to carry the barley 

 round and throw it against the case, and therefore any hard wood 



