TRANSACTIONS OF SECTION K. 789 
Pfeiffer found that the loss of nitrogen in untreated manure was 17:2 per cent., 
which compares with a loss of 19°5 per cent. in the presence of kainit. The loss 
of nitrogen when kainit was used by Immendorff was 21:3 per cent., the loss in 
the untreated manure not being given in his tentative report so far available. 
Schneidewind did not experiment with kainit. The results of these experiments 
are in complete relative agreement, and show that the loss of nitrogen is greater 
when kainit is used than when it is withheld. 
Effects of Superphosphate—This substance was spread twice daily over the 
litter in the stall at the rate of ‘75 kg. per 1,000 kg. live weight. The results 
obtained were as follows :— 
| —— Loss per cent, of Total Nitrogen 
| 
| 
\ 
In untreated dung When super. used 
Hansen and Giinther : . 
Pfeiffer ce boa eae OE 17:20 20°80 
| Immendorff . rh Phe BA ale 19°80 
With superphosphate, as with kainit, the loss of nitrogen during the storage 
of dung has been increased. It may, however, be mentioned that Hansen and 
Giinther and lmmendorff found that superphosphate conserved nitrogen to an 
appreciable extent so long as the dung lay in the stall, but that its effects disappeared 
whenever its acid phosphate and free sulphuric acid had been neutralised by 
ammonia, and this rapidly occurred in the pit. 
Effects of Precipitated Phosphatic Gypsum.—tThis at the rate of 1 kg. per 
1,000 kg. live weight was tried by Hansen and Giinther and Immendorff, the 
substance employed containing fully 8 per cent. P,O,. It was spread twice daily 
on the litter in the stall. The result obtained by Hansen and Giinther was that 
after lying for seventeen weeks in the pits the manure that had been untreated 
had lost 10°35 per cent. of nitrogen, whereas that treated with the phosphatic 
gypsum showed a loss of 14°47 per cent. The loss of nitrogen found by Immen- 
dorff when this substance was used amounted to 19°8 per cent. This substance, 
like the others, would therefore appear to be valueless as a fixer of nitrogen. 
Effects of Gypsum.—This substance has long been recommended as an agent 
for conserving nitrogen in the dung-heap. The results of its use, spread twice 
daily on the litter in the stall at the rate of 1 ke. per 1,000 ke., live weight, in the 
experiments conducted by Hansen and Giinther, were that in the presence of 
gypsum the loss of nitrogen amounted to 11:89 per cent., which compares with a 
loss of 8°56 per cent. when nothing was mixed with the dung. 
Schneidewind, using a much larger quantity of gypsum, namely, 5 lbs. per 
100 lbs. of dung, found that the loss of nitrogen was reduced from 35°69 per cent. 
to 15:22 per cent. In this connection he says: ‘The use of gypsum has markedly 
reduced the loss of nitrogen. Assuming the conserved nitrogen to have a good 
action on the crop, this agent may be said to have paid. But as the bulk of the 
nitrogen so conserved was found to consist of slow-acting albuminoid compounds, 
and seeing that the sulphate of lime was largely reduced to sulphides, which are 
directly injurious to plants, we cannot conclude that the use of gypsum has been 
profitable. Investigations with this substance will, however, be continued.’ 
Hansen and Giinther carried their experiments the length of using the various 
lots of manure on crops, but this part of their researches was hardly more favour- 
able to the use of conservation agents than the other. They thus express them- 
selves: ‘When the various manures were used on crops, five times in six the 
treated manure acted no better than the untreated. Only on one occasion was an 
improvement observable. Field and pit experiments alike have proved that the 
conservation agents employed are of no value.’ Schneidewind expresses himself 
equally forcibly when he says: ‘ As the result of many experiments conducted by 
ourselves and others, we have arrived at the conclusion that chemical substances 
are valueless as conserving agents.’ 
Pfeiffer also tried sulphuric acid sprinkled over the manure as it was placed 
