VALUE OF MANURES. 213 



tion of bones and acid nscd per acre in Mr. Tremayne's 

 experiment is unusually large ; the quantity now recom- 

 mended is 4 bushels of fine bone-dust, weighing" about 180 lb. 

 to 80 lb. of concentrated sulphuric acid, the common oil of 

 vitriol of the shops not being sufficiently strong for the 

 purpose. The following experiment was made on Treverbyn 

 estate in Probus, by Mr. J. Kendall, on a barley arish 

 (stubble), the soil of a light loamy character, resting on 

 brown arenaceous slate, and valued at 25,s-. per acre. 



No. Manure per acre. Cost. Produce. 



]. — 12 bushels of bone-dust and 2 cwt. of sulphuric 



acid 60s. . . 20 tons. 



2. — 20 bushels of bone-dust and 1 cart-load of 



wood-ashes 68 .. 18 J 



3. — Dry superphosphate 64 . . 20 



4. — 3 cart-loads of wood-ashes and 3 cart-loads of 



field-ashes 33 .. 8 



The object Mr. Kendall had in view in making the experi- 

 ment was to test bones in three ditii^'ereut ways at about the 

 same expense. The superphosphate took the lead at the 

 commencement, and continued it throughout. The rajudity 

 of growth is seen in every experiment made with superphos- 

 phate, which is of essential importance ; for the turnip is a 

 plant which exposes a large surface of leaf to the atmosphere, 

 and on this depends its ])ower of obtaining organic matters 

 from the atmosphere. The next experiment is a trial of 

 Ichaboe guano against the dry superphosphate, by Mr. C. 

 Parks, at Newlyn, on a wheaten arish, the soil of a deep 

 loamy character, resting on arenaceous slate, and valued at 

 25s. per acre. The extent of land was 5 acres. 



Produce 

 No. Manure per acre. Cost. without tops. 



1. — 25 cwt. of Ichaboe guano 22s. 6d. . . 13^ tons. 



2. — 22 cwt. of superphosphate 22 6 .. 16^ 



He had several experiments of this character before him, 

 and in every instance the superphosphate proved to be a very 

 cheap manure, and rapid in its fertilizing properties. J. S. 

 Enys, Esq., of Enys, tried the superjihosphate on a piece of 

 sparry soil, resting on coarse argillaceous slate, near Carclew 

 downs, valued at 10s. Gd. per acre. On 27 rows, measuring 

 29,403 square feet, manured with 2 cwt. of Ichaboe guano, 

 the weight of turnips without to])s was 8 tons i)er acre ; 

 whilst on 22 rows, measuring 24,948 square feet, manured 

 with 2 cwt. of superphosphate, the weight of bulbs averaged 



