No. VIII] EXPEKIMEtfrS UPON POTATOES, BARLEY AND OATS. 9 



lar and consistent result was obtained tliat 2 cwt. per acre caused no alteration 

 whatever in the weight of the produce upon either of the two oi|wiiich the tiiala 

 were made. Of the respective qualities of the crops nothing is stated. 



7°. Sidphate with nitrate of soda. — The above result with sulphate of soda 

 alone, is the more remarkable from the known effect produced by this and other 

 sulphates when mixed with nitrate of soda. This year, also, the mixture of 

 nitrate with sulphate of soda added one-half (G tons per acre) to the crop, a 

 greater proportionate increase even than in the experiment of 1841, which gave 

 an increase of 8 tons out of a total produce of 30 tons per acre. But this 

 season Mr. Fleming has tried, with still greater success, a mixture of 1 cwt. 

 each of sulphate of magnesia and nitrate of soda, the produce rising by the use 

 of this top-dressing to 22* tons. The relative effects of the two sulphates 

 would have been more clearly proved, had the proportions of nitrate of soda 

 applied per acre in the two mixtures been the same. 



8°. Nitrates of soda and potash. — Anotlier interesting fact to add to those 

 alrerdy registered upon the relative efficiency of these two saline substances, is 

 presented in page 49. One hundred weight and a half of— 



Nitrate of soda gave 16 tons. 



Nitrate of potash gave 18^ tons. 



This difference may have been due to accidental causes — or the 18^ tons of 

 the one result may have contained no more food than the 16 tons of the other; 

 but the multiplication of accurate experiments will eventually lead us to the 

 trutli. Apparent failures and discordant results must not discourage the prac- 

 tical man. By recording all trust-worthy results, the light will almost sponta- 

 neously spring up at last, 



9*^. Silicate of potash. — The results obtained by the use of this substance, and 

 the remarks appended to them (p. 50), are deserving of much attention. In re- 

 ference to this compound, and to the silicate of soda, I beg the reader to turn to 

 the suggestions contained in this Appendix, p. 40. 



10°. Mixed manures. — The mixtures in page 50 will no doubt be imitated, 

 and by those who can obtain them oihwwn composition, comparative experi- 

 ments may be tried with advantage both to theory and to practice. 



C. — The Experiments upon Barley. 



The true practical value of the experiments upon barley will be shown by 

 placing them in the following form : — 



Increase. £ a. d Cost per bush. 



Nitrate of soda with common salt, gave 5 bush, for 17 6 — 3s. 8d. 



Sulphate of soda with sulphate of magnesia, 7i bush, for 15 6 — 2s. Id. 

 Guano (at 25s.), .... 17 bush for 3 18 — 4s. 7d. 



Co.mmon salt, 6 bush, for 4 6 — Os. 9d. 



TurnbuU's artificial guano, . . 2 bush, for 1 4 — 12s. Od. 



The cheapest application, without doubt, upon this soil, is common salt. 

 At half the above price guano would produce the barley at 2s. 3d. per bushel, 

 and the larger quantity reaped, together with the value of the straw in the pre- 

 paration of manure, may satisfy many that either guano or the mixture of sul- 

 phates may be used with profit. It is a further recommendation of tlie common 

 salt, however, that it produced the heaviest, while guano produced tlie lightest 

 grain. 



From the experiment with nitrate of potash no result can fairly be drawn, in 

 consequence of the great drought of the season (see Mr. Gardiner's remarks). 



D. — The Experiments upon Oats, 

 1°. Negative effect of salitie manures. — The first of the two series of experi- 

 ments above recorded being made at Lennox Love — like those made at the same 

 place upon turnips — derive their principal interest from the illustration they 

 Kfford of the 7iegat.ive effect of saline manures upon the oat crop, under the in- 



