iv PREFACE. 



The experiments are so contrived, that the apparatus required is of the 

 most simple and inexpensive kind in most instances, and due regard lias 

 been paid throughout to simplicity and usefulness, rather than mag- 

 nificence ; the object being to render everything as plain and intelligible 

 as possible, commensurate with the subject. 



The introductory narratives are all founded upon facts, or are the actual 

 biographies of eminent scientific men. The lessons have been constructed 

 for weekly tuition, it being desirable that the first five days should be 

 devoted to catechising, and the sixth to recapitulation, examination viva 

 voce, or essay writing upon the subjects contained in the week's course 

 of study. 



Teachers are recommended to give additional illustrations of the 

 subjects under consideration, to perform the experiments given in the 

 lessons before the pupil, and to adduce other familiar and simple experi- 

 ments to elucidate them. 



Pupils should perform the experiments themselves before studying the 

 lessons, and repeat them again when master of the lesson. If possible, 

 they should also perform other experiments bearing upon the question, 

 and explain their analogy to those previously exhibited. 



Each lesson has a few important questions appended, to assist the 

 teacher in the examination of the pupils. 



