CONTENTS. 



Introductory Resiarks on the progress of scientific 



knowledge 1 



Influence exerted by chemical discoveries on the commerce and 

 prosperity of nations — Repugnance of farmers to "book 

 farming" — Changes which have taken place in the opinions 

 which were formerly entertained respecting the application 

 of science to agricidture — Recent progress of practical 

 agriculture — Introduction of guano and bones — Ser\aces 

 which chemistry is capable of rendering to the farmer 

 — Ancient state of agriculture in Ireland — Remarkable pro- 

 ductive powers of the soils of this country — Knowledge and 

 energy required for their proper cultivation — Defects of the 

 education at present acquired by -farmers — Objects of the 

 lessons — Obstacles to the progress of agricultural knowledge 

 — Professional education necessary to the farmer — Methods 

 which he should pursue in studying the scientific principles 

 of his art — Sources from which his crops obtain their food — 

 Distinction between simple and compoimd bodies — elements 

 which contribute to the growth of plants and minerals — List 

 of simple apparatus and specimens to be procured by agri- 

 cultural teachers and pupils. 



.CHAPTER I. 



Account of the materials from which plants are formed 19 



Essential conditions for the growth of plants — Properties of the 

 atmosphere — Meaning of the term mixture as distinguished 

 from chemical combination — Illustrative experiments — 

 Decomposition — Nature of the substances of whioh tlie 

 atmosphere is composed — Properties of oxygen gas, and its 

 influence on animal and vegetable life — Instructions for the 

 preparation of gases — Experiments for illustrating the pro- 

 perties of oxygen, nitrogen — Ammonia, carbonic acid — 

 Definition of terms used in agricultural works — Experiments 

 by which the existence of ammonia in the atmosphere was 

 tietermined — Proportion in which carbonic acid exists in 

 plants — Its existence in water — Its action on the materials of 

 the soil. 



