liv PEOCEEDINGS OF THE 



Turning then to some of the botanical results of the experiments, he 

 explained the contents of a wall-case showing the principal results 

 of the botanical separation of grasses and other meadow-plants in 

 1867, the twelfth year of experiments which still continue to be 

 made on the mixed herbage of permanent grass land.* 



Other rooms besides the chemical department and museum were 

 visited, including the furnace, drying, balance, gas-analysis, calcu- 

 lating, and store rooms, and the members were then conducted by 

 Dr. Gilbert through the " allotment gardens " to the experimental 

 farm. The rain, percolation, and other gauges were first examined. 

 There are two rain-gauges, one of the usual construction and five 

 inches in diameter, and the other square, one-thousandth of an 

 acre in area, and with a plate glass edge. The three gauges for 

 the determination of the quantity and composition of the water 

 percolating through the soil are also one-thousandth of an acre in 

 area, and are respectively 20, 40, and 60 inches deep, the soil they 

 contain, with its subsoil, being in its natural state of consolidation. 

 In addition to these gauges to each of the differently manured 

 plots of the permanent experimental wheat-field, there is a separate 

 drain-pipe, so that the drainage-waters can from time to time be 

 collected and analysed. 



The private grovmds adjoining the residence of Mr. Lawes in 

 Rothamsted Park were then entered, and, after passing in front of 

 the house, and thence through a fine avenue of lime trees, whose 

 arching branches, rooting in the soil and then uprising in a 

 dense tangle of young shoots, form most picturesque leafy corridors, 

 the members arrived at a portion of Mr. Lawes' park about 8 acres 

 in area, divided into 24 plots varying from one-eighth to half an 

 acre each. Dr. Gilbert here explained the treatment each plot 

 received and some of the most important results obtained. 



The first plots examined showed that mixed alkalies alone, while 

 they improve the character of the herbage, but little increase the 

 quantity of pi'oduce ; that nitrate of soda penetrates the soil and 

 encourages the growth of deep-rooted plants which are not much 

 affected by drought ; and that it is impossible to get out in the 

 produce any large amount of manure of any kind which has been 

 put into the land, about two-thirds of the nitrogen supplied being 

 unrecovered in the increase of crop when ammonia-salts are applied, 

 and only about one-half when nitrate of soda is employed. 



In a plot (No. 3) to which no manure had ever been applied, the 

 average of four botanical separations, at intervals of five years each, 

 gave 49 species of grasses and other plants, the order Leguminosse 

 contributing about 9 per cent. ; in another (9), where ammonia salts 

 had been added to mineral manure, the number of species was 

 reduced to 29, there being only one leguminous plant ; and in the 

 next (10), to which, with the exception of potass, the same manure 

 had been applied, there was not a single leguminous plant left, 



* A paper on this subject, by Mr. J. J. Willis, has been communicated to the 

 Society, and published in the ' Transactions,' Vol. II, p. 140. 



