(NB) New chemical effects are constantly being discovered which are startling and unexpected in their results even to the initiated, and much more so to those who have made no special study of the subject. | -iTSj'-cv:; Uniform With this Volume MECHANICS A N D SOME OF ITS MYSTERIES. FLYING AND MYSTERIES. SOME OF ITS P L A Y B O O K S O F S C I E N C E CHEMISTRY AND CHEMICAL MAGIC BY V. E. J O H N S O N , AUTHOR " THE THEORY OF "EGYPTIAN . SCIENCE" AND PRACTICE OP MODEL AEROPLANING " ETC. OVEFC ONE HUNDRED AND FIFTY EXPERIMENTS AND NUMEROUS ILLUSTRATIONS LONDON HENRY HODDER FROWDE AND 1912 STOUGHTON PREFACE THIS is one of a series of little volumes dealing with the lighter and more amusing sides of science, and therefore properly termed "playbooks." In each the author's aim has been the same: to provide boys with material for intelligent amusement, in the course of which they will bring into play qualities that will serve them well in matters of greater importance. Every endeavour has been made to render the volumes up-to-date. Of the various experiments described a large number are original; and where selected they have generally been presented in a novel form. They have almost without exception been personally performed by the author, and every one is quite practicable if due care and a little patience be exercised. Different volumes will naturally appeal to different readers. The amateur conjurer will naturally find most to interest him in the volume on Chemistry and Chemical Magic; the budding airmail will turn with more zest to the volume on Aeronautics; the future engineer to that on Mechanics and Mechanical Appliances. What is important is that each boy should be encouraged in his proper bent. Every boy, like my Uncle Toby, should ride a hobby-horse of some kind; and an .
