100 Sir J. B. Lawes and Prof. J. H. Gilbert. [Jan. 9, 



soil and seed at the commencement, in the soil and produce at the 

 conclusion, and the gain. Lastly, in the last column but one, the 

 total gain, reckoning in each case, the initial nitrogen = 1 ; and, in 

 the last column, the gain in the plants, reckoning the nitrogen in the 

 seed = 1. 



[The results relating to the soils in pots 1, 2, and 3, are calculated 

 from the copper oxide determinations ; which gave, in the dry sand 

 at the commencement (as already shown) 0*00245 per cent, nitrogen ; 

 and at the conclusion the amounts were : — 0*00269 in that of pot 1, 

 0*00239 in that of pot 2, and 0*00208 in that of pot 3. The deter- 

 minations in the garden soil were by the soda-lime process, and were 

 only made to obtain a general idea of the result, and were not 

 intended for exact quantitative estimates of gain or loss. Thus, the 

 higher the percentage of nitrogen, the smaller the quantity that can 

 be taken for burning, whilst such a soil, rich from the application of 

 dung, is a very heterogeneous mixture, and difficult to sample for 

 analysis. It, moreover, contains a very large amount of carbon, and 

 gives a coloured acid for titration. 1ST or was the nitric acid deter- 

 mined, either at the commencement or at the conclusion; but, with 

 so much organic matter the error, if any, thus arising would be 

 immaterial. The determinations were, however, fairly accordant for 

 such material ; giving, calculated on the dry soil, at the commence- 

 ment, 0*4341 and 0*4379, mean 0*4360 per cent. ; and at the 

 conclusion, 0*4378 and 0*4342, mean 0*4360. It may be added, that 

 a difference or error of 0*01 in the percentage of nitrogen in the soil, 

 would represent a gain or loss of 0*204 gram on the quantity of the 

 garden soil used. The data upon which the amounts of nitrogen in 

 the seed, and in the products of growth, are calculated, have been 

 already considered. — January 24, 1890.] 





Nitrogen. 





In soil. 



In see 



ds and produce. 



Total. 



In total 

 products, 

 total 

 initial 

 = 1. 



In 



plants, 

 nitrogen 

 in beed 





At com- 

 mence- 

 ment. 



At 

 con- 

 clusion. 



Gain( + ) 

 or 



loss (— ). 



In 



seeds 

 sown. 



In 

 total 

 plants. 



Gain. 



At com- 

 mence- 

 ment. 



At 

 con- 

 clusion. 



Gain. 



Pot I... 



Pot 2... 

 Pot 3 .. 

 Pot 4... 



grams. 

 -0999 

 -0999 

 -0999 

 7 -9989 



grams. 

 0-1096 

 0-0974 

 -0848 

 7 -9989 



gram. 

 + 0-0097 

 -0-0025 

 -0-0151 



gram, 

 -0293 

 -0298 

 0-0291 

 0'0301 



gram. 

 -2822 

 0-5361 

 -4357 

 0-6600 



gram . 

 -2529 

 0-5063 

 0-4066 

 -6299 



scrams. 

 0-1292 

 0-1297 

 0-1290 

 8 -0290 



grams. 

 0-3918 

 -6335 

 -5205 

 8-6589 



gram. 

 6 -2626 

 -5038 

 0-3915 

 -6299 



3- 03 



4- 88 

 4-04 

 1-08 



9 -63 

 17-99 

 14-97 

 21 -93 



The first point to notice is, that there is very little difference in the 

 amount of nitrogen in the soils at the commencement, and at the 

 conclusion, of the experiments. There would, doubtless, be some 



