84 THE POPULAR SCIENCE MONTHLY. 



" There are now more than thirty thousand bottles of samples of 

 experimentally grown vegetable produce, of animal products, of ashes, 

 or of soils, stored in the laboratory. A botanical assistant is also oc- 

 casionally employed, with from three to six boys under him, and with 

 him is generally associated one of the permanent general assistants, 

 who at other times undertakes the botanical work." Several com- 

 puters and record-keepers have for some time past been occupied in 

 calculating and tabulating the field, feeding, and laboratory results. 

 Additional chemical assistance is frequently engaged in London and 

 elsewhere. Professor Way, Dr. Frankland, and Dr. Voelcker, have 

 done more or less work on material obtained at Rothamsted, and their 

 published reports are of great interest. Mr. R. Richter, of Berlin, has 

 for some years past been almost constantly occupied with analytical 

 work sent from Rothamsted. A considerable, but of course varying, 

 force of agricultural laborers find employment in the field-work. 



" The general scope and plan of the field experiments has been to 

 grow some of the most important crops of rotation, each separately, 

 year after year, for many years in succession on the same land, with- 

 out manure, with farm-yard manure, and with a great variety of chem- 

 ical manures ; the same description of manure being, as a rule, applied 

 year after year on the same plot. Experiments on an actual course of 

 rotation, without manure and with different manures, have also been 

 made. In this way experiments have been conducted as follows : 



" With wheat, thirty-nine years in succession : thirteen acres, thirty- 

 seven plots, many of which are duplicates of others. On barley, thirty- 

 one years in succession : four and a half acres, twenty-nine plots. On 

 oats, ten years (including one year fallow) : three quarters of an acre, 

 six plots. On wheat, alternated with fallow, thirty-one years : one 

 acre, two plots. On different descriptions of wheat, fifteen years : 

 four to eight acres (each year in a different field), now more than 

 twenty plots. On beans, thirty-two years (including one year wheat, 

 and five years fallow) : one and a quarter acre, ten plots ; also twenty- 

 seven years : one acre, five plots. On beans, alternated with wheat, 

 twenty-eight years : one acre, ten plots. On clover, with fallow or a 

 grain-crop intervening, twenty-six years : three acres, eighteen plots. 

 The land is now devoted to experiments with various leguminous 

 plants, commenced in 1878. On turnips, twenty-eight years (includ- 

 ing three years barley) : about eight acres, forty plots. On sugar- 

 beets, five years : about eight acres, forty-one plots. On mangold- 

 wurzel, seven years : about eight acres, forty-one plots. On potatoes, 

 seven years : two acres, ten plots. On rotation, thirty-five years : about 

 two and a half acres, twelve plots. On permanent grass-land, twenty- 

 seven years : about seven acres, twenty-two plots. 



"Comparative experiments, with different manures, have also been 

 made on other descriptions of soil, in other localities. Samples of all 

 the experimental crops are taken, and brought to the laboratory. 



