4 5
Water 75·42 73·90
Soluble organic matters 3·71 2·70
Soluble inorganic matters
Silica 0·254 0·147
Phosphate of lime 0·382 0·129
Lime 0·117 0·018
Magnesia 0·047 0·018
Potash 0·446 0·960
Soda 0·023 0·082
Chloride of sodium 0·037 0·052
Sulphuric acid 0·058 0·072
Carbonic acid and loss 0·106 0·584
—— 1·47 —— 2·06
Insoluble organic matters 12·82 14·39
Insoluble inorganic matters—
Soluble silica 1·424 1·10
Insoluble silica 1·010 1·54
Oxide of iron, alumina, and phosphates 0·947 0·37

1 2 3
Containing phosphoric acid(0·178)(0·177)(0·298)
Equal to bone earth(0·386)(0·277)(0·646)
Lime 1·120 1·291 1·868
Magnesia 0·143 1·029 0·078
Potash 0·099 0·127 0·208
Soda 0·019 0·046 0·038
Sulphuric acid 0·061 0·099 0·098
Carbonic acid and loss 0·484 0·929 1·077
—— 4·05 —— 4·90 —— 7·47
—— —— ———
100·00 100·00 100·00
Containing nitrogen 0·149 0·270 0·170
Equal to ammonia 0·181 0·320 0·206
Containing nitrogen 0·494 0·470 0·580
Equal to ammonia 0·599 0·570 0·700
Total nitrogen 0·643 0·740 0·750
Equal to ammonia 0·780 0·890 0·906
4 5
Containing phosphoric acid(0·274)(0·06)
Equal to bone earth(0·573)(0·10)
Lime 1·667 2·25
Magnesia 0·091 0·02
Potash 0·045 0·12
Soda 0·038 0·01
Sulphuric acid 0·063 0·10
Carbonic acid and loss 1·295 1·44
—— 6·58 —— 6·95
—— ———
100·00 100·00
Containing nitrogen 0·297 0·149
Equal to ammonia 0·360 0·180
Containing nitrogen 0·309 0·613
Equal to ammonia 0·375 0·744
Total nitrogen 0·606 0·762
Equal to ammonia 0·735 0·924

On examining and comparing these analyses, it appears that the differences are by no means great, although, on the whole, they tend to show that, weight for weight, well-rotten dung is superior to fresh, provided it has been properly treated. Not only is the quantity of valuable matters existing in the soluble state materially increased, whereby the dung is enabled to act with greater rapidity, but, owing to evaporation and the escape of carbonic acid, produced by the decomposition of the organic substances, the proportion of those constituents which are most important to the plant is increased. This is particularly to be noticed, in regard to the nitrogen, which has distinctly increased in all cases in which the dung has been kept for some time; and the practical importance of this observation is very great, because it has been commonly supposed that, during the process of fermentation, ammonia is liable to escape into the air. It would appear, however, that there is but little risk of loss in this way, so long as the dung-heap is left undisturbed; and it is only when it is turned that any appreciable quantity of ammonia volatilizes. It is different, however, with the action of rain, which soon removes, by solution, a considerable quantity of the nitrogen contained in farm-yard manure; and the deterioration must necessarily be most conspicuous in rotten dung, which sometimes contains nearly half of its nitrogen in a soluble condition. The effect produced in this way is conspicuously seen, by the results of weighings and analyses of small experimental dung-heaps, made by Dr. Voelcker at different periods. The subjoined table shows the composition of the heap, lying against a wall, and exposed to the weather at different periods:—

When Put up.
Nov 3d 1854. April 30th 1855. Aug 23d 1855. Nov 15th 1855.
Weight of manure in lbs. 2838 2026 1994 1974
Water 1877·9 1336·1 1505·3 1466·5
Dry Matter 960·1 689·9 488·7 507·5
Consisting of—
Soluble organic matter 70·38 86·51 58·83 54·04
" mineral matter 43·71 57·88 39·16 36·89
Insoluble organic matter 731·07 389·74 243·22 214·92
" mineral matter 114·94 155·77 147·49 201·07
Total nitrogen 18·23 18·14 13·14 13·03
Equal to ammonia 22·14 22·02 15·96 15·75

In this case, during the winter six months, which were very dry, the manure lost 541·8 lbs. of water and 270·2 lbs. of dry matter, but the nitrogen remained completely unchanged. But during the succeeding semi-annual period, when rain fell abundantly, the quantity of nitrogen is diminished by nearly a third, while the water has increased, and the loss of dry matter by fermentation, notwithstanding the high temperature of the summer months, was only 182·4 lbs. The soluble mineral matters also, which increased during the first period, are again reduced during the second, until they also fall to about two-thirds of their maximum quantity. That this effect is to be attributed to the solvent action of rain is sufficiently obvious, from a comparison of the results afforded by the other heaps, which had been kept under cover during the same period, as shown below.

When Put up.
Nov 3d 1854. April 30th 1855. Aug 23d 1855. Nov 15th 1855.
Weight of manure in lbs. 3258 1613 1297 1235
Water 2156·0 917·6 563·2 514·5
Dry Matter 1102·0 695·4 733·8 720·5
Consisting of—
Soluble organic matter 80·77 74·68 53·56 66·28
" mineral matter 50·14 54·51 39·55 54·68
Insoluble organic matter 839·17 410·24 337·32 341·97
" mineral matter 131·92 155·97 303·37 257·57
Total nitrogen 20·93 19·26 16·54 1·79
Equal to ammonia 25·40 23·33 20·08 2·81

The loss of nitrogen is here comparatively trifling, and during the whole year, but little exceeds two pounds, of which the greater part escapes during the first six months, and the soluble inorganic matters are almost unchanged. The total weight of the manure, however, undergoes a very great reduction, due chiefly to evaporation of water, but in part also to the loss of organic matters evolved in the form of carbonic acid during fermentation.