GIVEN OFF BY PLANTS DURING THEIR GROWTH. 



51 



were also cut from the wheat grown by the unmanured and 

 the mineral manured soil, as well as from all of the bai ley jars, 

 on May 26th ; the holes in the glass covers having become in 

 these cases quite choked up. These cuttings were much more 

 considerable in quantity than the former, and of course also 

 considered as a part of the experimental product. 



The several clover plants were respectively cut when in full 

 flower. The pea with mineral manure was cut on August 4th, 

 and that in the unmanured soil on August 11th. All the other 

 plants, viz., wheat, barley, and the beans, were harvested on 

 September 7th. 



The corn of the peas and beans was well developed and 

 tolerably ripened : that of the wheat and the barley was by no 

 means so much so, especially that of the wheat. This was sup- 

 posed partly to arise from a want of water, the plant having an 

 appearance of drying up rather than healthy ripening. It is 

 seen, indeed, by reference to Table L, at page 45, that the 

 amounts of water derived from the soil were greater in the 

 cases of one of the wheat jars and two of the barley jars than in 

 the others, though the exhaustion, in this respect, of the beans, 

 one of the peas, and one of the clovers was not much less. It 

 had been remarked, however, from the commencement, that the 

 apparent demand for supplied water was much greater in pro- 

 portion to that given off in the cases of the gramineous plants 

 than in the several leguminous ones ; but it seems generally to 

 have been found by experimenters that the cereals were much 

 more difficult to bring to maturity under the somewhat artificial 

 circumstances usually provided in experiments of this kind than 

 any other plants. 



The irregularities of cuttings and want of uniformity in the 

 final maturation of the produce will be guarded against as far as 

 possible in our future experiments. To these indeed may pro- 

 bably be chiefly attributed any want of definiteness or consistency 

 in the results about to be considered ; and it was on account of 

 them deemed unnecessary to take the fresh weights of the pro- 

 duce of the jars. 



The plants cut level with the surface of the perforated lids 

 shortly after being taken from the jars were dried in a stove at 

 about 140°, and then carefully stored for future examination. 



Recurring to the subject for the purpose of this paper, the 

 corn plants were carefully dissected — the seeds from the straw, 

 chaff, &c. Each of them was then exactly halved. The one 

 portion of corn and one each of straw, chaff, &c. (the latter 

 being mixed together), were fully dried at 212° — the weight 

 taken and then burnt to ash, and the other specimens, the corn 

 separately from the straw, chaff, &c, being reserved for the 

 determination of their nitrogen. The cuttings were also halved 



e 2 



