740 



It was observed that the uitroueii coiiibinations decreased during 

 fermentation. At tlie bejiinninj? there was lO-S.l ing. of a:nmoniaeal 

 nitrogen, at the end 150.S mg., an excess of 51 nig. If we add to this 

 the milligrams corresponding to the 8.79 liters of ammonia gas evolved, 

 we have practically^ the 61 mg. of loss shown by analysis. Tlie loss of 

 organic nitrogen is therefore practically equal to the gain in ammo- 

 niacal nitrogen; or in other words, the nitrogen given up by the organic- 

 matter is converted into aininoiiia. 



The figures also show that during the fermentation the manure h)st 

 less oxygen and hydrogen than was found in the evolved gas. This 

 excess of oxygen and hydrogen must have been supplied by the mois- 

 ture present, as has been maintained by Liebig to be the case under 

 such circumstances. 



iSummary. — In marsh-gas fermentation at 52'^ C. nu ^;i,st(»us nitrogen 

 is producecl. Xo nitrogen eompounds are fornuMl by the fixatiiui of 

 ammonia l>y the organic matter; on the contrary, nitrogen is given off 

 in the form of ammonia. Water assists in the decomp(Ksiti«>n()f organic 

 matter, furnishing to the carbon a certain amount of oxygen and 

 hydrogen. 



Effect on the total yield of potatoes of removing the tubers 

 from time to time, E. WoUny ^ Foisdi. mi/, tl. dth. il. mir. I'liiisiK. 

 li^pp.l^5—iW). — In the vicinity of Euroi>ean cities, where there is a 

 demand for early potatoes, farnuTs follow the practice of digging into 

 the hills before the tubers are all ripe and removing such as are large 

 enough for cooking, Tiie soil is tlu-n replaced and tlie others allo\ve«l 

 to grow. This may be repeated two or three times during the develop- 

 ment of the plant. Since it has been claimed that by this means the 

 yield is increased, the effect of this praefiee on the total yield of 

 potatoes was made the subject of investigation. In 18SS, isst», is'.m^ 

 and 1891 a large number of (lilVerent varieties of j)otat4>es. including 

 both early and late, were grown for (he test. The large tubers were 

 removed from some of the plants of each variety once before the final 

 harvest, from others twice and three times, and on still others they 

 remained undisturbed until all were dug. In «'veiy case from twenty 

 to thirty i)lants received the same treatment. The I'onclusions from 

 the results are that the total yield of tubers where they were renn>ved 

 once or more during the growing season wa« larger in number but less 

 in weight than where the i>lants reuuune<l undisturbed until ripe. In 

 general the disadvantageous inlluence of fractional harvesting on the 

 weight of the total yield was more noticeable the earlier and the oftener 

 the tubers were removed. 



Stachys tuberifera. — This new vegetable,* aecording to a descrip- 

 tion (»f it given l»y Dr. L. Just {Dvut. lamhc. Pressc, lS!fl, p. ;?<§;*) is of 

 Japanese origin and belongs to the Labiatra'. The elongated small 

 white tubers, the part used for food, grow on the cmls oi stolouiferous 



