136 The Rothamsted Grass Experiments. 



report closes with a summary of the most prominent results 

 of the whole inquiry up to date (1863). The sixth and last 

 report that appeared in the R.A.S. Journal gives an account 

 of the produce of hay per acre, the chemical composition of 

 the hay, and the amount of certain constituents removed 

 from the land in the fourth, fifth, sixth, and seventh seasons 

 of the experiments. 



Since 1863 the R.A.S. Journal has been silent as to the 

 results of this unique series of experiments on the herbage of 

 permanent meadow ; but on June 19, 1879, Dr. Lawes and 

 Dr. Gilbert read before the Royal Society a paper bearing the 

 title, " Agricultural, Botanical, and Chemical Results of 

 Experiments on the Mixed Herbage of Permanent Meadow, 

 conducted for more than Twenty Years in Succession on the 

 Same Land. Part I." The following year this communica- 

 tion was printed in extenso in the " Philosophical Transactions 

 of the Royal Society," and occupies no less than 130 of the 

 large quarto pages of that publication. Since it embraces 

 the results of more than twenty years' observations, it was 

 obviously unnecessary, as implied above, to enter at any 

 length into a discussion of fhe first few years' results. The 

 investigators arrange and consider the results obtained under 

 three separate heads, dealing respectively with the agricul- 

 tural, the botanical, and the chemical results. Part I., now 

 under notice, treats principally of the agricultural results, 

 and these we proceed to examine. 



Without manure, the produce of hay has varied from about 

 8cwt. to nearly 39cwt. per acre, and the average yield has 

 been about 23cwt. per acre per annum. But the plot most 

 heavily artificially manured, and yielding the best, has given 

 an average of about 64cwt. of hay per acre per annum, the 

 extremes being 40cwt. and 80cwt. The results on the 

 other differently manured plots vary greatly within these 

 extremes. At the same time, the botanical composition of 

 the herbage has varied most strikingly, so that, starting 

 with some fifty species of plants on the unmanured land, any 



