22G PEOCEEDINGS OF THE CHEMICAL DEPARTMENT. 



with muriate is there any increase worth noticing, and then it is 

 only to the extent of a single ton. It is worthy of notice, how- 

 ever, that the largest result is attained where guano, sulphate of 

 ammonia, and muriate of potash are applied together ; but the 

 increase over the same manure, and ammonia alone, is trifling. 

 In this case it must be borne in mind that in plot 8 the quantity 

 of ammonia is only half as large as in plot 2 ; and it might there- 

 fore be alleged that the muriate of potash produced the same 

 effect as the sulphate of ammonia, which it replaced. But this 

 view can scarcely be maintained in the face of the entire absence 

 of effect in other cases. It is much more probable that it is due 

 to the quantity of ammonia contained in the manure, when that 

 substance is used alone, being in excess of the requirements of the 

 crop. In point of fact, the evidence both of last and this year's 

 experiments tends to show that the effect of ammonia on the 

 turnip is comparatively small. Thus, in the experiments before 

 us, phosphoric acid doubles the crop, and ammonia only adds 3 

 tons per acre more, and this quantity requires only 15 lbs. of 

 ammonia, while the manure contained 56. It is also interesting 

 to notice, that there is no appreciable difference between glue and 

 ready-formed ammonia. 



Experiments made by Mr Smith, West Drums, Brechin. 



The field in which these experiments were made is a light 

 black soil on the Old Eed Sandstone, in fair cultivation and con- 

 dition. It had been pastured for three years, after which two 

 crops of oats had been taken, the second of which got 2 cwt. of 

 guano per acre. The land was prepared in the usual way, and 

 sown on the 20th June. The crop brairded regularly, and was 

 thinned on the 13th July. The plots continued to grow pretty 

 equally, except No. 13, which at no time surpassed the nothing 

 plots, and ultimately fell behind them. The season was un- 

 favourable to turnips throughout. The crop was weighed on 

 28th December, and the results are contained in Tables VII. 

 and VIII. 



These experiments give very concordant results, and the con- 

 clusions they lead to correspond generally with those which pre- 

 ceed. Muriate of potash alone has no effect, but when associated 

 with other substances appears to produce a slight increase. It 

 does so along with soluble phosphates to a slight extent, but the 

 largest crops are produced when these two substances and 

 ammonia are conjoined. Glue likewise produces as good an 

 effect as the ready-formed ammonia. 



Experiments made by Mr Drennan, Holmston, Ayr. 



The experiments were made on a rather heavy loam, which 

 was selected on account of its apparent uniformity of quality. 



