JV PEEFACE. 



ter for the pupil to learn and other matter not so essential by a difference 

 in type is always awkward, and is not fully effectual. 



3d. While most books on Chemistry are illustrated chiefly from phenom- 

 ena developed in the laboratory of the chemist, I have taken great pains to 

 have abundant illustrations from common every-day phenomena, so that 

 this book is largely a Chemistry of Common Things. As an illustration of 

 the general neglect on this point, I find that very few of all who have 

 studied ordinary chemical books, or have attended lectures, can explain the 

 chemistry of so very common a thing as striking fire. 



4ith. The arrangement of topics is entirely different from that of any 

 other text-book on Chemistry. It is such that the most simple and inter- 

 esting topics come first, and each page enables the pupil to understand bet- 

 ter the pages that follow. I begin with making the pupil familiar with the 

 four grand elements, oxygen, nitrogen, carbon, and hydrogen, and their 

 combinations with each other. This brings out fully those most interesting 

 of chemical subjects, combustion, water, and the chemistry of the atmos- 

 phere. I then pass to the combinations of these four elements with other 

 elements, and the combinations of these latter with each other. In this 

 portion of the book I notice first the metals and their compounds with oxy- 

 gen the oxides ; then the metalloids sulphur, phosphorus, etc., and their 

 combinations with oxygen the oxygen acids, and also the hydrogen acids. 

 Then in natural sequence come to view the salts formed by the union of 

 these acids and oxides, and in connection with these the salts of the chlorine 

 family. Now follows a development of the laws of chemical affinity, the 

 examples being taken from the facts already brought out, so that we have 

 here in part a review of what is gone before, which is of great advantage to 

 the student. In this connection I introduce the consideration of chemical 

 equivalents, symbols, and the atomic theory. All of this is commonly in- 

 troduced into the first part of Chemistry, and hence is generally but par- 

 tially understood, and is very diy and uninteresting ; but on the plan which 

 I have adopted the pupil easily comprehends it, and is interested at every 

 step. Then comes in. naturally the influence of the modifiers of chemical 

 affinity heat, light, electricity, and magnetism which before have been al- 

 luded to here and there, but now are fully treated of. The hook concludes 

 with the consideration of Organic Chemistry. 



