EXPERIMENTAL STATIONS. 203 



each soil as carefully and minutely as the present state of our 

 knowledge regarding the constitution and mutual action of the 

 various ingredients therein permits. It is a laborious and difficult 

 task, and it must be confessed that we are as yet far from possessing 

 a knowledge of the numerous and complex reactions which go on 

 in soils, or a satisfactory means of arriving at a just estimate of 

 the effect of their various ingredients upon plant life. But a series 

 of experiments upon a variety of soils would do much to advance 

 our knowledge in that direction. It would be a great advantage 

 to agriculture, and would immensely inhance the value of the 

 experiments being carried on at the Society's station, if farmers 

 in different parts of the country, who have time and aptitude for 

 that kind of work, would repeat upon their own lands any of the 

 sets of experiments described in the accompanying scheme. I 

 would be glad to give to those who would do so any aid in my 

 power. The value of the information which would be derived 

 would amply repay the trouble, and would come to the assistance 

 of the Society's experiments in that direction in which they are 

 necessarily defective. 



The differences due to climate are to be contended with in a 

 similar way, and those which arise from the accidental circum- 

 stances of weather may be diminished by continuing the experi- 

 ments during a long period of years. Experiments carefully 

 conducted gain value year by year, and a soil which for a series 

 of years has been treated accurately with a manure becomes a 

 kind of pedigree land which is invaluable for experiment. 



The Highland and Agricultural Society have been fortunate 

 in securing for their two stations pieces of land which are very 

 different in their character and origin, and which are fairly repre- 

 sentative of a large part of the arable land of the Lothians. That 

 of Harelaw (Longniddry) is a deep loam overlying limestone, 

 which has had a considerable effect in giving a character to the 

 soil. It is near the sea, exposed on all sides, having a fine 

 natural drainage, and is one of the earliest districts in Scotland. 

 The station at Pumpherston overlies the carboniferous forma- 

 tion, is a thin boulder clay, situated upwards of 300 feet above 

 the sea-level, and is in a colder, damper, later district than the 

 other. Here, then, the soils and climatic conditions are very 

 different, and these will no doubt have a marked effect on the 

 manures and on the crops. 



The extent of ground which should be used for comparative 

 experiments is a question regarding which there are great dif- 

 ferences of opinion. In the opinion of some, experimental plots 

 should be as small as possible, without being too small ; and 

 the 7^2^^^ P^^'^ ^^ ^^^ ^^^^ -b^^ been selected by them as being the 

 most convenient. It is our opinion, however, that such plots 

 should be as large as possible, without being too large, and ^ 



