THE CHEMISTRY OF COMMON LIFE. BY JAMES F. JOHNSTON, M.A., F.R.S., F.G.S., ETC., ETC., AUTHOR OF "LECTURES ON AGRICULTURAL CHEMISTRY AND GEOLOGY,' A CATE ILLUSTRATED WITH NUMEROUS WOOD ENGRAVINGS. VOL. I. EIGHT EDITION. NEW YORK: D. APPLETON AND COMPANY, 346 & 348 BROADWAY. M.DOOO.LVI. DEDICATION. TO SIR DAVID BREWSTER, K.H. D.C.L. F.R.S. V.P.R.S., EDINBURGH, ASSOCIATE OF THE INSTITUTE OF FRANCE, AND PRINCIPAL OF ST. LEONARD'S COLLEGE, ST. ANDREW'S. MY DEAR SIR DAVID, I dedicate this little Work to you, partly that I may have the honour of associating with it a name so eminent in science as yours, and partly for the opportunity it gives me of expressing my sense of the many obligations I owe you as an old and tried friend. Being yourself not only a lover and assiduous cultivator of science, but a remarkable extender of its boundaries-a leader in one of its most interesting and intricate departments-and an anxious diffuser of the results of general scientific research-I am certain of your sympathy in the following attempt to render popular some of the more immediately applicable results of that branch to which I have myself been now long devoted. If we, whose profession it is to follow the progress of science, can scarcely keep pace with the advance of our several departments, it must be especially necessary, from time to time, to present its more striking novelties, in an intelligible form, to the general public. With sincere wishes that your health may be long preserved, and that optical science may still for many years number you among its most illustrious cultivators, DURHAM, October, 1853. Believe me, MY DEAR SIR DAVID, Your obliged friend, JAMES F. W. JOHNSTON. INTRODUCTION THE common life of man is full of wonders, Chemical and Physiological. Most of us pass through this life without seeing or being sensible of them, though every day our existence and our comforts ought to recall them to our minds. One main cause of this is, that our schools tell us nothing about them-do not teach those parts of modern learning which would fit us for seeing them. What most concerns the things that daily occupy our attention and cares, are in early life almost sedulously kept from our knowledge. Those who learn any thing regarding them, must subsequently teach themselves through the help of the press: hence the necessity for a Popular Chemical Literature. It is with a view to meet this want of the Public, and at the same time to supply a Manual for the Schools, that the present Work has been projected. It treats, in what appears to be their natural order, |