Agricultural Chemistry — Turnips. 



537 



on re-weigliing the following morning were found to have lost 

 more than 6 per cent. If the leaves gathered in the evening had 

 not been weighed for drying until the following morning, an error 

 of 1 per cent, or more in the estimation of dry matter would thus 

 have arisen. We have elsewhere stated that 100 oz. specimens 

 of green wheat-plant lost invariably from 7 to 9 per cent, during 

 the process of separating from each other the leaves^ the ear, and 

 the stem, although two persons were employed in the operation. 



Again, five turnips, with their leaves, were found to weigh as 

 soon as gathered 16 lbs. 4-^ oz. ; after exposure two days and 

 nights upon straw, under cover, they v/eighed 15 lbs. 5^ oz. ; 

 and after three days and nights more, 14 lbs. 85 oz. Thus, if 

 after being gathered 48 hours, 100 oz. had been taken for a 

 drying experiment, it w^ould have been equivalent to 106 oz. of 

 fresh plant; and if after five days, to 112 oz. Five plants were 

 next taken, and the leaves cut off, leaving, perhaps, two inches of 

 stem upon the bulbs. The turnips, thus freed of their leaves, 

 weighed 12 lbs. 8J oz. ; after 48 hours on straw, under cover, 

 12 lbs. 4Joz. ; and after 3 days more, 11 lbs. 3J oz. In this 

 case, 100 oz. taken after being gathered 48 hours would have 

 represented 102 oz. fresh bulb; and after 5 days, 106 oz. These 

 turnip experiments were made in cold October weather ; but the 

 amount of loss sustained would of course depend much upon 

 the vigour of growth of the plant, upon the state of the weather 

 at the time, and the temperature of the place where the plants 

 were kept. 



It is evident, then, that very serious errors may arise when 

 specimens are received from a distance, or even when they are 

 not, unless special precautions be taken, according to the nature 

 of the produce under examination. Indeed it is exceedingly 

 difficult, when fully aware of these circumstances, so to conduct an 

 extensive series of comparative experiments on green or succulent 

 substances as to obtain results which shall be both actually and 

 relatively to each other open to no objection. 



When, in the experiments quoted above, bulbs with the leaves, 

 or the leaves alone are taken, the loss is seen to be much greater 

 than when the bulbs alone are operated upon. This is what 

 might have been anticipated, and shows clearly that the effect is 

 due to the continuance of the natural circulatory processes of the 

 leaves after removal from the land. 



In operating upon bulbs or roots which are in contact with the 

 soil, we meet with a difficulty of another kind. In such cases 

 there is always a quantity of soil adhering to the specimens, 

 which, if not removed, will affect to some extent the determination 

 of dry matter, and still more seriously that of the mineral matter. 

 A single bulb may be cleaned sufficiently by careful picking and 



