Analyses of Ashes of Plants. 



175 



such experimental trials, but rather force upon our attention the 

 absolute necessity of conducting them in a scientific spirit. No- 

 thing can be done effectually in the way of establishing agricultural 

 statistics of this description unless attention be paid to every 

 circumstance of the means employed and the result obtained. 



We would not be thought to draw any other conclusion from 

 these data than such as would convey a sense of the great caution 

 •necessary in all such experiments. That artificial manures may 

 have a tendency in some cases to produce watery^ ill-conditioned 

 ('■'dropsical/' as was said of the potato) plants is quite possiblcj 

 and it is no less proved^, both from our experiments and from the 

 observations of practical men, that two crops may be widely dis- 

 similar in their solid contents. 



It is by no means an unusual thing for a farmer to remark, 

 that a piece of turnips ha;s carried so many head of sheep longer than 

 from Its appearance he would have expected. ^lay not this be 

 due to the circumstance which we have endeavoured to explain ? 

 Be it remembered that a given weight of turnips which would 

 afford food to a flock of sheep for a fortnight, supposing that they 

 contained 90 per cent, of water, would carry the same sheep 3 

 weeks if the quantity of water were only 85 per cent. That far 

 greater differences than this really exist, the table before given fully 

 proves, and, as we before said, this subject demands the most 

 patient and rigorous examination. In all experiments on the 

 growth of rootSj it would be easy to make the corrections we have 

 spoken of by selecting one or two healthy turnips from each lot;, 

 separating the tops, and after carefully removing the dirt by a 

 brush and a little water, and slicing the bulbs, setting the whole 

 to dry in a gentle oven or other moderate heat ; they should be 

 w^eighed at intervals of a week till they cease to lose weight. The 

 original weight and that of the turnips when dry being known, 

 we obtain the solid matter of the acre by an easy calculation. 



This plan will afford the most certain data short of a chemical 

 analysis of the constituents of each crop, by which alone we can 

 ascertain whether the solid matter be always alike in character. 



And now we come to consider the mineral matter in the turnip. 

 One column of the table (page 173) affords us the information 

 that 100 parts of turnip bulb, in its ordinary condition, may con- 

 tain from '48 to 1'13 pans of mineral matter. These are extreme 

 cases. The mean per centage of the bulb- ash in all the speci- 

 mens is '73. There is here certainly a very considerable latitude 

 in the quantity of mineral matter in different specimens of the 

 same root, a latitude which is not accounted for by the variations 

 in the proportions of water in the plants. This will at once be 

 seen by inspection of the column in the table which gives the ash 

 on the dri/ vegetable. The ash given by turnip-tops is in almost 



