176 Experiments upon Swedes. 



Plot VII. — Manured with superphosphate at the rate of 3 cwt. 

 jier acre. 



Produce .. 10 tons 17 cwt. 16 lbs. 

 Increase . . 4 tons 5 cwt. 1 qr. 20 lbs. 



From first to last this experimental plot had the lead as to 

 appearance, and the result of the weighings showed that it yielded 

 in reality the best crop. 



The superphosphate used in this experiment had the following 

 composition : — 



Moisture lOvSO 



* Organic matter 4'21 



Biphosphate of lime 20'28 



Equal to bone-earth, rendered soluble by acid .. (31"63) 



Insoluble phosphates 4'11 



Hydrated sulphate of lime (gypsum) 4f)'63 



Alkaline salts (common salt) 10'78 



Insoluble silicious matter (sand) 3'19 



_ 100-00 



': * Containing nitrogen '34 



Equal to ammonia '41 



I need hardly say that this is an excellent superphosphate, 

 which, at 11. lO^., the price at which it was sold, is an exceed- 

 ingly cheap manure. The price of all raw materials employed 

 in the manufacture of artificial manures having gone up very 

 much since the beginning of this season, I hardly think it pos- 

 sible that the maker of this superphosphate can supply his 

 customers this season with an article quite so rich in soluble 

 phosphate at 11. 10s. per cwt. But should the proportion of 

 bone-earth rendered soluble by acid be only 22 or 23 per 

 cent., and the manure be prepared equally dry and tine as hitherto, 

 I have no hesitation in saying, that such a superphosphate at 

 11. 10s. will be 2/. or 3/. cheaper than most samples which 

 I analysed during this season. 



It is worthy of notice, that this superphosphate contained very 

 little ammonia, but an appreciable quantity of salt, which I have 

 no doubt added to its efficacy ; for I find that other superphos- 

 phates, rich in soluble phosphates, and containing a considerable 

 proportion of ammonia, but no salt, had not near so good an 

 effect upon the turnip-crop in ]857. 



Plot VIII. — Manured with 3 cwts. of fine bone-dust per 

 acre : — 



Produce .. 8 tons 11 cwt. 2G lbs. 

 Increase ., 1 ton I'J cwt. 2 qrs. 2 lbs. 



Til is bone-dust was extremely well pounded, being as fine as 

 the finest sawdust. 



