IV CONTENTS. 



CHAPTER 11. PAGE 



Materials which water is capable of supplying to plants 34 



Its composition — Steam — Properties and preparation of hydro- 

 gen gas — Distillation — Solid matters discovered in the water 

 of springs and rivers — Importance of water to the growth of 

 plants — Climate of Ireland — ^its influence on farm work — 

 Evaporation — Advantages of thorough draining. 



CHAPTER HI. 



Materials existing in the soil which contribute to the 

 growth of plants 42 



Potash — Potassium — Carbonate of Potash — Compounds of Soda 

 — Lime — forms in which it exists in Ireland — Gypsum — 

 Magnesia — Magnesian limestone — Oxides of iron and man- 

 ganese — Properties of Silica — Mode in which it is rendered 

 soluble in water — Chlorine — Properties of sulphuric acid — 

 Phosphoric acid — Phosphate of lime — Importance of the 

 inorganic matters discovered in the ashes of plants — Amount 

 of inorganic and organic matters which cultivated plants 

 contain. 



CHAPTER IV. 

 Substances into which plants convert the simple elements 



on which they live 51 



Nature of the compounds produced by plants — method of obtain- 

 ing these compoimds for examination — "Woody fibre — 

 Cellular tissue — Manufacture of starch — Composition of starch 

 — its transformation into sugar — production of British gum 

 and starch sugar — Varieties of gum — Mucilage — Albumen of 

 the potato — Gluten, method of preparing it from wheat-flour 

 — its composition — Casein — Diastase — Fatty matters, oils, 

 and acids, which are found in plants — Composition of linseed- 

 cake — Quantity of oil and fatty matter in wheat-flour — 

 Purposes which these compounds are designed to serve — 

 Changes by which plants convert the materials of the soil and 

 air into food for man. 



CHAPTER V. 



Structure of plants, and changes which accompany their 

 growth i 63 



The seed — Changes which take place when barley is converted 

 into malt — Parts of which plants consist — Conditions 

 necessary for the development of the seed — Growth of the 

 plant — Course of the sap — Effects produced by plants on the 

 atmosphere — Arrangements by which the imiformity of its 

 composition is maintained — Experiments of various chemists 

 — Influence of light on plants. 



