PROGRESSIVE FARMING. 33 



blind." But those who, like a distinguished member of this So- 

 ciety, devote themselves to an investigation of the relations 

 which chemistry sustains to agriculture, and test their theories 

 in the field before giving them to the public, are entitled to the 

 thanks of the whole community. It is only by the efforts of 

 such men that agriculture can be raised to the rank of a science. 

 A great hindrance which every observing farmer meets, is the 

 length of time required to try an experiment. If we are desir- 

 ous of ascertaining the comparative value of certain modes of 

 culture, or certain special crops, we find we can make only one 

 trial in a year ; and some experiments, such as those relating to 

 the application of manures, require more than a year to deter- 

 mine the result. And here we discover another important cause 

 of the slow progress of agricultural science. The most care- 

 fully conducted experiment is liable to mislead, by reason of the 

 many influences which affect the crop during its growth. 



It is only by careful and repeated trials that the farmer be- 

 comes certain of the superiority of any particular method. 

 And even then, the effect he attributes to one cause may be 

 owing to another. The increased crop, which he thinks is due 

 to some special fertilizer, may be in consequence of some slight 

 natural difference in soil, or amount of moisture, or other un- 

 seen cause. To illustrate : — Perhaps no class of experiments 

 would be more valuable to farmers than a carefully conducted 

 trial to ascertain the comparative value of the different kinds of 

 food commonly used for milch cows. We should naturally think 

 that by carefully measuring the food, and changing from one kind 

 to another, the question might, after a few days' experience, be 

 decided. But every dairyman knows that the quantity of milk 

 varies from day to day for other reasons. Extreme heat or 

 cold, drink at irreguler intervals, or the want of it, to say nothing 

 of other causes, so modify the amount of milk produced, that it 

 is next to impossible to determine with exactness how much the 

 difference in the quantity of milk is owing to the difference in 

 quality of the food consumed. We find a like difficulty in other 

 experiments in husbandry. There are so many causes operat- 

 ing, which we can neither understand nor control, that it is not 

 easy to determine how much of any effect is due to any one of 

 them. 



5* 



