AgNO3......... 25 K2Al2(SO4)4...... 50 BaCl2......... 50 KBr.... 25 Ba(N0 3)2........ 30 K2Cr207........ 50 CaClz......... 60 KI.......... 25 Ca(OH)2...... saturated KOH....... 60 CaS04....... saturated NaICOS........ 50 CUC12 50 NaOH 60 Cu(N03)......... 50 NalSl03....... saturated FeS04......... 50 NH,N03........ 50 HgC12......... 30 Pb(C2H302)2...... 50 HgN03..... 25 + 25 HN03 Pb(NOs)2....... . 50 Other solutions....saturated. Indigo solution (sulphindigotic acid) is prepared by heating for several hours over a water bath, a mixture of ten parts of H 2SO4 with one of indigo, and, after letting it stand twenty-four hours, adding twenty parts of water and filtering. TEXTBOOK ADVERTISEMENTS THAT APPEARED IN THE ORIGINAL EDITION INTRODUCTION TO CHEMICAL SCIENCE By R.P. WILLIAMS, Instructor in Chemistry in the English High School, Boston. l2mo. Cloth. 216 pages. By mail, 90 cents; for introduction, 80 cents. This work is strictly, but easily, inductive. The pupil is stimulated by query and suggestion to observe important phenomena, and to draw correct conclusions. The experiments are illustrative, the apparatus is simple and easily made. The nomenclature, symbols, and writing of equations are made prominent features. In descriptive and theoretical chemistry, the arrangement of subjects is believed to be especially superior in that it presents, not a mere aggregation of facts, but the science of chemistry. Brevity aud concentration, induction, clearness, accuracy, and a legitimate regard for interest, are leading characteristics. The treatment is full enough for any high school or academy. Though the method is an advanced one, it has been so simplified that pupils experience no difficulty, but rather an added interest, in following it. The author himself has successfully employed this method in classes so large that the simplest and most practical plan has been a necessity. Thomas C. Van Nuys, Professor of Chemistry, Indiana University, Bloomington, Ind.: "I consider it an excellent work for students entering upon the study of chemistry." C.F. Adams, Teacher of Science, High School, Detroit, Mich.: "I have carried two classes through Williams's Chemistry. The book has surpassed my highest expectations. It gives greater satisfaction with each succeeding class." J.W. Simmons, County Superintendent of Schools, Owosso, Mich.: "The proof of the merits of a textbook, is found in the crucible of the class-room work. There are many chemistries, and good ones; but, for our use, this leads them all. It is stated in language plain, interesting and not misleading. A logical order is followed, and the mind of the student is at work because of the many suggestions offered. We use Williams's work, and the results are all we could wish. There is plenty of chemistry in the work for any of our high schools."