610 Mil. J. I!. DAWES, DB. GILBEBT, LND DB. PUGB 



which 4*6 were absorbed by potash, and the remainder proved to be combustible. 

 Hence, up to this date, there has been no appreciable evolution of fr< _"n. In 



order to see whether the organic matter present would reduce a nitrate, with the evolu- 

 tion of free Nitrogen, about 5 grammes of saltpetre were now put into the vessel, and 



it was replaced in the same room as before. 



May 3, 1859. — Several times since December !"_'. 1858, when the nitrate of pol 

 was put in, the vessel lias been warmed up to 30° C. ; but up to tin, date very little ga* 

 has been evolved. 



May 25, 1859. — Still very little gas evolved; 4 cub. cent, only collected, one-fourth 

 of which was carbonic acid, and the remainder was combustible. The \. qow 



placed in the sunlight again, but up to the middle of June no further evolution of sat 

 had taken place. The fluid, still contained nitrate of potash. The vesa 1 was then half 

 filled with oxygen in order to sec if this would cause a renewal of the de< tion. 



After ten days a portion of the gas was examined, when it was found that not one-fourth 

 of the supplied oxygen had been consumed — a result which was quite unexpected. The 

 total gas being removed, the vessel was again nearly filled with oxygen, driving out the 

 greater part of the fluid, and leaving the partly decomposed seeds in an atmosphere of 

 this gas. The apparatus so arranged was placed in the sunlight, and remained there 

 during some very warm weather. 



July 12, 1859. — The gas collected contained in 100 parts — 



Carbonic acid. Oxygen. -Nitrogen. 



20 79 1 



By accident a small quantity of air was admitted into the vessel, so that the analysis 

 can only be taken to show how exceedingly slow was the oxidation of organic matter 

 which had been treated as this had been. 



On the removal of the matters from the vessel, the Beans were found to possess much 

 of their original firmness and solidity. The other seeds, though they retained their 

 form, were softer, and they had evidently undergone a more complete decomposition. 

 They emitted very little odour, which was not unpleasant. 



There can be no question as to the absence of any evolution of free Nitrogen during 

 the long period that these three descriptions of seed were under experiment. A very 

 small proportion of the combined Nitrogen present would, if set free, have been sufficient 

 to fill the vessel with gas. But, as has been seen, only a few bubbles of gas were evolved 

 during several months. 



Several other experiments were made upon the products of the decomposition of 

 organic matter, in the first stages of the process. In Table X., which follows, are given 

 the amounts, and the composition, of the gas obtained from decomposing organic matter 

 in a few out of a number of cases in which we have had occasion to observe them — 

 including, for comparison, some of the results already referred to. The decomposition 

 took place in water, in vessels similar to that used in the experiments last described 

 (fig. 7, Plate XII.). 



