AGRICULTUKAL KNOWLEDGE. 297 



chemical, geological, botanical, and physiological research. 

 In the expression of these principles, new words — the 

 names, for example, of certain substances familiar to the 

 chemist or botanist — are necessarily employed. These 

 words or names must be understood, if the sentence in 

 which they are contained is to be comprehended — as the 

 child is shown pictures of the horse and the lamb, or is 

 taken to the fields to see these animals, if it is to 

 understand the early reading-lessons in which they are 

 mentioned. But a thing is known by its sensible 

 properties ; and as a child at once distinguishes the 

 apple, the potato, the turnip, and the onion, by their 

 form, colour, taste, and smell, so, among the things 

 chemistry deals with — phosphorus and sulphur, oxygen 

 and nitrogen, starch and gluten, must be made familiar 

 to his senses, if he is to understand the meaning of their 

 names. Thus far experimental chemistry is necessary 

 in the teaching of agricultural principles. It must make 

 the words intelligible, but no more is necessary. With 

 the apparatus or book in his hand, however, the master 

 (if the purpose of his teaching be not clear to his own 

 mind) is apt to introduce other unnecessary experiments 

 or scientific explanations, burdening the memory of the 

 boy, and distracting his attention. The school-inspector, 

 also, not distinguishing more clearly the true line of 

 agricultural teaching, sometimes encourages this, by 

 requiring and expecting, at his examinations, a know- 

 ledge of purely chemical principles, which are necessary 

 neither to the comprehension nor to the future appli- 

 cation of the agricultural principles which are intended 

 to be inculcated. A teacher must learn to resist the 

 temptation to show a pretty experiment, even with the 

 laudable desire of making his pupils see and feel its 

 natural beauty, for the boy will naturally ask, " How 

 does this apply to agriculture ? " It requires a clearer 

 head and more considerable knowledge than many 



