By Edward Solly, Esq. 49 



It must be borne in mind that these experiments were made on 

 garden ground, the composition and nature of which is very 

 variable and uncertain, and far too rich to enable positive deduc- 

 tions to be formed of the relative value of the different substances 

 employed as manure. The general inference furnished by the 

 above table is, that those plants having the largest and most vigo- 

 rous tops, produced the largest quantity of tubers ; but that the 

 tubers of these plants were the poorest in azotised matters. It is 

 also worthy of remark, that those tubers which are richest in 

 azotised matters, are also those which contain the greatest relative 

 proportion of inorganic matter. Thus selecting from the fore- 

 going table the three tubers richest, and the three poorest in 

 azotised matter, we have 



Mean. 



The earthy ingredients of the haulm and tubers, were for the rea- 

 son above adverted to, not examined in detail ; but a general analysis 

 of the whole series was made, the results of which sufficiently 

 show, that the nature of the earthy ingredients both of the haulm 

 and of the tubers, but more particularly of the former, varied very 

 greatly. The following tables exhibit the proximate composition 

 of these inorganic matters, divided into Alkaline salts, earthy salts, 

 and siliceous matter : the first head including Carbonate, Phos- 

 phate, Sulphate, and Muriate of Potash and Soda ; the second, 

 soluble as well as insoluble Salts of Lime and Magnesia, together 

 with Oxides of Iron and Manganese. Both tables are arranged in 

 the order of the quantity of Alkaline matter which the substances 

 contained. 



in. 2nd. series. 



