XX INTRODUCTION. 



tion, i.e., as a sort of primer that might be referred to with the 

 object of developing an inclination towards scientific study and 

 logical habit of thought. It has not been attempted to deal with 

 the whole range of physical science and elementary chemistry, but 

 only with the general outward properties of natural objects and 

 the things surrounding us, and the ways in which these become 

 modified by the action of one thing upon another, either alone or 

 when aided by the application of heat ; and as a sort of further 

 study, with some of the general phenomena connected with Heat 

 and Light. Should the occasion arise, other branches of physical 

 science, such as Acoustics, Magnetism, Electricity, and the 

 Physical Forces of Nature generally, will be similarly treated in 

 a companion volume. 



It is quite a mistake to suppose that costly appliances and an 

 elaborately fitted laboratory are indispensable to carry out scientific 

 experiments, more especially those of an elementary character. 

 Of course, for the illustration of the more recondite points, such as 

 exact measurements and quantitative physical and chemical deter- 

 minations, such accessories are generally requisite ; although, even 

 in such matters as these, wonderfully accurate valuations can often 

 be made by careful and experienced hands with eminently simple 

 appliances. For certain experiments where rare, and consequently 

 costly, materials are indispensable (e.g., experiments requiring the 

 use of platinum vessels, palladium foil, &c.), it is obviously im- 

 practicable to obtain the desired result without incurring expense ; 

 but for by far the larger majority of the experiments described 

 only simple and inexpensive apparatus are required, such as test- 

 tubes and flasks, glass tubing and perforated india-rubber corks, 

 stands of various shapes and such like, obtainable for at most a 

 few shillings, or even pence, from any of the numerous dealers in 

 scientific apparatus. 



For certain chemical experiments where evil-smelling gases like 

 sulphuretted hydrogen, or corrosive and injurious vapours like 

 bromine and hydrofluoric acid, are necessarily evolved, when a 

 properly fitted "fume chamber" or "stink cupboard" is not avail- 

 able, a room with door and windows wide open, so as to produce 



