ASH OF THE TURNIP, CARROT, PARSNIP, AND POTATO. 219 



3°. How large a proportion of lime exists in the straw of the pea and 

 of the vetch — compared with that of the hean — and how much larger the 

 proportion is in all the straws than in any of the grains — and 



4°. That the quantity of silica in pea straw is double of what is con- 

 tained in the straw of the vetch, and 4 limes that of the bean straw. 



The produce of straw from these three varieties of pulse is very bulky, 

 but varies in weight from 1 to If tons — or is on an average about 2300 

 lbs. per acre. The produce of grain is still more variable. 



The bean gives from 16 to 40 bushels, of about 63 lbs. 

 The pea . . 12 to 84 *' " 64 lbs. 



The vetch . . 16 to 40 " ♦' 66 lbs. 



The mean return from beans is estimated by Schweriz [Anleitung 

 Zum Praktischen Ackerbau, II., p. 346,] at 25 bushels (1600 lbs.), from 

 peas at 15 bushels (1000 lbs.), and from vetches at 17 bushels (1100 

 lbs.) per acre. 



The quantity of the several inorganic matters, therefore, carried off 

 from an acre in the straw of these crops, will be about 2^ times the 

 weights given in the table — and in the grains, where the crop is near 

 the above average, 1| times the weights in the tables for beans and for 

 peas, and for vetches very nearly the actual weights above given. 



VI. OF THE ASH OF THE TURNIP, CARROT, PARSNIP, AND POTATO. 



These four roots, as they are carried from the field, contain respective 

 ly in ten thousand pounds — 



TURNIP. CARROT. PARSNIP. POTATO. 



--^-. 



Roots. Leaves. Rods. Tops. 



23-86 32-3 35-33 20-79 40-28 81-9 



10-48 22-2 9-22 7-02 23-34 0-9 



7-52 62-0 6-57 4-68 3-31 129-7 



2-54 5-9 3-84 2-70 3-24 17-0 



0-36 0-3 0-39 0-24 0-50 0-4 



0-32 1-7 0-33 0-05 0-32 0-2 



Potash 



Soda . 



Lime . 



Magnesia 



Alumina 



Oxide of Iron 



Oxide of Manganese — — 0-60 — — — 



Silica .... 3-88 12-8 1-37 1-62 0-84 49-4 



Sulphuric Acid . 8-01 25-2 2-70 1-92 5-40 4-2 



Phosphoric Acid . 3-67 9-8 5-14 1-00 4-01 19-7 



Chlorine . . . 2-39 8-7 0-70 1-78 1-60 5-0 



63-03 180-9 66-19 41-80 82-83 308-4 



These roots, as already staled (note, p. 178), contain very much water, 

 so that, in a dry slate, the pr(yportion of inorganic matter present in them 

 is very much greater than is represented by the above numbers. I 

 have, however, given the quantities contained in the crop as it is carried 

 from the field, as alone likely to be of practical utility. 



The crops of these several roots vary very much in different localities, 

 being in some places twice and even thrice as much as in others — every 

 nine tons, however, which are carried off the ground, contain about 

 twice the weight of saline and earthy matters indicated by the numbers 

 in the table. 



