No. VIII.] KXPERIMKNTS ON TURNIPS. 47 



crops, but, as far as known, had never been previously green-cropped. The whole 

 of it received the same labour, preparatory to sowing, and the weather during the 

 operation (-which lusted four days) was the same, ilius giving to each experiment 

 an equal chance. I'he peiiod of sowing was from the 15th to 19th of May ; the 

 turnip seed used was Skirving's improved purple-topped yellow; the dung used 

 was the produce of the farm, and, with the exception of the foreign guano, all the 

 other manures applied were those manufactured and sold by Mr. Turnbull, of 

 Glasgow. 7%(? extent of ground for each expcrijueni was one acre, Scotch measure. 



No. 



Kind of Manure. 



Farm-yard DuHg. . . 



Humu.s 



Farm-yard Dung. . . 



Hnmu's' . 



Artificial Guano. ... 

 Farmyard Dung. . , 



Prepared Bones' 



Farm-yard Dung 



Humus 



Improved Bones. . . 



Artificial Guano 



Ammoniacal Salts.. 



Artificial Guano 



Guano 



Quantity 



per 

 imperial 

 Acre. 



12 tons. 



2 cwl. 

 12 tons. 



\i cwt. 



12 tons. 

 2^ cwt. 

 12 tons. 

 90 lbs. 

 90 " 



45 

 31 cwt. 

 3l 



31 cwi 



3| " 



Cost of Produce 

 Miuiure j in Bulbs 

 per impe- per impe- 

 rial Acre, rial Acre. 



7 

 6 

 4 4 

 U 15 

 4 4 



24 



20 



9i « 



28 " 



Cost for 

 Manure 

 per ton. 



s. d. 

 3 3i 



IV. Effect of Gypsum on the Turnip Crop. 



In 1841, Mr. Burnet of Gadgirth, near Ayr, applied a top-dressing of gypsum 

 to part of a field of turnips, and found that it naarly doubled the crop. « 



In 1842, Mr. Campbell, of Craigie, in the same neighbourhood, "dressed a 

 six acre field, with the exception of a few rows, with two cwt. of unburned 

 gypsum per acre. The crop over the whole was excellent, but there was no 

 perceptible difference between the dressed and the undressed part." 



How are these discordant results to be reconciled 1 The following questions 

 suggest themselves as worthy of investigation — 



1°. Is gypsum realty propiiioiis to the turnip crop, — and to every variety alike? 



2°. Are the unlike results above obtained to be ascribed to the abundant pre- 

 sence, in the one case, of gypsum in the soil, or in the manure ploughed in, 

 and its absence in the other — or to the variety of ttirnip cultivated 1 — or 



3°. Can the sea-spray supply gypsum to Mr. Campbell's estate, which is 

 within two miles of the coast, while it is less bountiful to that of Mr. Burnet, 

 which is six miles inland 1 



B.— EXPERIMENTS ON POTATOES. 



I. Results obtained by Mr. Campbell, of Craigie. 



Four equal drills of potatoes were treated as follows: — 



J °. Guano, 3 cwt. per aCre produce 5 pecKs, 



2°. Farm-yard dung, 40 cubic yards per acre . . . produce 6 do. 

 3°. Do., top-dressed afterwards with 60 lbs. of nitrate of soda, produce 6 do. 

 4°. Do., top-dressed with 160 lbs. sulphate and nitrate, mixed, produce 6 do. 



* TurnbuWs Humus is formed from urine and night-soil mixed with gypsum and char- 

 coal and then dried. 



Turnbull^ s prepared Bones are bones and flesh dissolved in muriatic acid, and mixed 

 with about an equal quantity of charcoal in powder. 



TurnbulVs Artificial Guano is, I believe, prepared bones, with a little salt and sulphate of 

 ammonia prepared from urine, and dried wiL; i. stove-heat. 



