58 



INVESTIGATION INTO THE AMOUNT OF WATER 



would be more nearly equal in the case of this Series than in the 

 former one, and also that the per centage of it was higher in the 

 specimens of the second Series than in those of the first — a result 

 which would have to be attributed to the more or less direct 

 influence of the manure. 



The plants of Series 3, having- an ammoniacal manure, were 

 so manifestly unhealthy that the results afforded in relation to 

 them must not be allowed much weight, and indeed they appear 

 to be little worthy of confidence. 



In the lower section of Table VIII. the comparison is made 

 between the individuals of the same description of plant under 

 different conditions of soil. A considerable difference is here 

 shown to be coincident with the variations of manuring condition, 

 and, setting aside the clover, more especially in the cases of the 

 wheat and the peas. The composition of these when determined 

 may, to a great extent, elucidate the fact : indeed the varying 

 proportion of seed to straw in the several cases indicates a pro- 

 bable difference in this respect ; and analogy would also lead us 

 to believe that, with the varying observed degree of ripeness and 

 the experimentally ascertained varying amounts of ash, the per 

 centage of nitrogen in the several specimens of the same kind of 

 plant would also vary very greatly. In support of this opinion 

 we may state, that analyses already made of one of the products 

 show that some of the cereals contained nearly twice the ordinary 

 amount of nitrogen. The coincidences in this section are most 

 striking in reference to the beans, and these, as has been already 

 stated, were the most healthy and matured plants obtained from 

 the experimental jars. The three barley plants, it is true, show 

 a considerable uniformity, but, as has already been explained, 

 the figures given for the mineral manure plant are probably 

 somewhat in error. 



Notwithstanding these discrepancies, as yet not fully and satis- 

 factorily explained, we cannot but recognise in the results thus 

 far obtained a very encouraging significance, and, indeed, it 

 seems to us more than probable that future experiments may fix 

 a definite relationship between the amount of the rao?2-nitrogenous 

 proximates fixed in the plant, and this even probably to a great 

 extent irrespectively of their exact composition, provided their 

 source were mainly in each case the atmosphere, as in the in- 

 stances of the seeding plants now under consideration, and 

 accumulating, as they are known to do, their chief supplies 

 during the period of the most powerful influence of heat and 

 light upon the plants. 



In Table IX. the amounts of water passing through the plant 

 for each grain of substance fixed are given — the indications 

 being the inverse of those we have just been considering ; and 



