Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: ALKALIES. 11T. These are substances of great importance. They may be defined to be bodies which combine with acids, neutralize their powers, and produce salts. They are divided into three classes, thusi— 1. Those consisting of a metallic base united to oxygen, which are in number three—potass, soda, and Kthia.—II. That containing no oxygen—ammonia.—III. Those containing oxygen, hydrogen, and carbon;—these are some recently discovered vegetable alkalies, of which little is known. Besides the already-mentioned properties of alkalies, they possess the following also:—I. They change the purple colour of many vegetables to a green, the red to purple, the yellow to a brown. They also re-produce the purples which have been reddened by acids.—II. They continue in possession of this property, and retain their solubility in water, when saturated with carbonic acid; these properties distinguish them from the alkaline earths. —III. They have an acrid and urinous taste.—IV. They are powerful corrosives, or solvents of animal matter, with which, as well as with oils in general, they combine so as to produce neutrality: —V. They are decomposed or volatilized by a strong heat.—VI. With water they combine in every proportion; and with alcohol, very largely. 118. Potass, nfoxd alkali, produced from wood-ashes, and called on that account, the vegetable alkali. It is an oxide of the newly discovered metal, potassium. Potass, when pure, is solid, white, and extremely caustic. It changes the purple colour of vegetables to a green, and yellow to a brown. When exposed to the air, it rapidly attracts humidity from it, and becomes a liquid. In Chemistry it is employed very extensively, both in manufactures and as a re-agent in analysis. It is the basis of all the common soft soaps. Potass co...