BOOK REVIEW.

Study and Quiz Outline. BY WILLIAM LLOYD EVANS, Ph.D., Professor of Chemistry, Ohio State University. Ginn and Company, Boston, New York, Chicago, London, Atlanta, Dallas, Columbus, San Francisco; 1923. x + 163 pp. 2 diagrams. 20.5 X 14.0 cm.

To the average student beginning the study of chemistry the determination of what is of first importance usually causes much more difficulty than the subject matter itself. Confronted by the extensive array of chemical facts contained in the average text book, he is apt to be dismayed and discouraged at the very beginning of the course. This state of mind can be very largely overcome if, at this time, some instruction is given in the best methods of study. To offer such instruction is one of the purposes of Dr. Evans' book and, to the reviewer's mind, it succeeds very well.

The book is based on MacPherson and Henderson's "A Course in General Chemistry," but with a few minor exceptions, it is quite applicable to any standard text. As its title implies, it is divided into two parts, study outlines and quiz questions. There are study outlines for about 25% of the chapters, but not for the others, so that the student will be encouraged to apply the outline method to them and thus acquire proficiency in its use.

There is a set of quiz questions for each chapter. There are four types,standard quiz questions, numerous and well selected stoichiometrical problems, questions that cannot be answered by reference to some text but that require reasoning effort on the part of the student, and questions requiring the design of apparatus to investigate or illustrate various phenomena. The value of the two latter types in encouraging the use of reason rather than memory is quite evident. The quiz questions are fairly free from annoying ambiguity. Though there are quite a few "Discuss" questions, the extent of the discussion desired is usually clearly indicated The questions vary widely in the amount of detailed knowledge required to answer them, so that they may be suited to either quizzes or formal examinations. Equation writing is emphasized.

Two "production" diagrams are included. They are intended to show the relation of the more important compounds of an element to one another and to the parent element. The compounds of nitrogen and of sodium are offered as examples. The working out of such diagrams should be of great benefit to a student.

The only adverse criticism the reviewer can offer is that the modern electronic conception of oxidation-reduction reactions is stressed so lightly. Though the structure of matter and the electronic view of ionization are fully covered, electronic oxidation is scarcely touched upon. This is unfortunate since the latter furnishes the simplest and most generally satisfactory treatment of the subject. However this deficiency is one that is readily remedied. The reviewer feels that this is a most excellent book and one that any teacher can place with profit in the hands of his students. MALCOLM M. HARING

University of Maryland,

College Park, Md.

Entered as Second-class Matter, January 31, 1924, at the Post Office at Easton, Pa., under the Act of March 3, 1879. Acceptance for mailing at special rate of postage provided for in Section 1103, Act of October 3, 1917, authorized January 31, 1924.

Vol. I

APRIL, 1924

EDITORS' OUTLOOK

No. 4

As we view the paths of teachers, do we find Ruts or Research? One is following the line of least resistance when he teaches his course exactly the same way year after year; changing the text-book or revising the lectures means work for the teacher. And when we teach that bugbear, valence, for instance, in just the same way that we have taught it a dozen times before, we are prone to forget that it is only the first time the student has faced the subject. The good teacher needs to keep himself warm and fresh by coming in close touch with the simple things that are so difficult; he must see chemistry, not from his peak of superior knowledge, but from the valley of despair where his students are. That is trite, but important. Now a full appreciation of the difficulties demands thoughtful study of our successes and failures in teaching. An old teacher once boasted that he never taught his course two successive years without modification. If he saw no way to improve it, he would retrogress occasionally in order to progress in a new direction the following year! Such changes break up that mental "set" or "complex" or whatever it is that leads us into teaching ruts.

Every successful teacher must have an interest in research in chemical education. Whether he can carry on experimental or theoretical investigations that will fill the pages of our journals is not now the question. But should we not admit that the problems of teaching chemistry are of sufficient difficulty and importance to receive the same expert treatment that we give to the conventional objects of research? Whatever may be our attitude towards educational methods in general, every teaching laboratory should be also a place for research in teaching.

Our Society is placing a new value upon the teachers of chemistry in asking that the colleges and universities provide courses for prospective teachers. In these courses the neophyte will be taught approved methods of presenting the subject, details of laboratory administration, and similar important matters. But who knows that the present best is really best? Should we not go more deeply into the question by encouraging teachers to undertake definite research problems in connection with our methods of instruction?

An important step in this direction has been taken in the work of the Committee on the Correlation of High School and College Chemistry. This was a definite problem, much concerted effort has been expended upon it, and valuable results may be expected to follow. But this is only a beginning. The problems continue to come thick and fast even after we have successfully correlated the student into college!

There is the question of the chemical curriculum. Is our usual sequence of courses the best? Do we give honor where honor is due in the matter of emphasis? Is there any sort of correlation between the courses in chemistry and those in cognate sciences? Then each course is a wide field for research: content, order, emphasis, demonstration experiments, correlation of laboratory and lectures etc. And again there are problems in connection with the training of particular groups of students in relation to their subsequent careers, pre-medical, pre-engineering, etc. (The American Physical Society has just completed an interesting study of the instruction of pre-medical students in physics.) These questions are all of importance, not to mention such matters as laboratory administration, grading, forms of record, tests, laboratory design and materials, and so on. It is stimulating to see here and there a laboratory which is producing new ideas along these lines. The time is now ripe for a thorough investigation of such problems. Never until the establishment of THIS JOURNAL has there been a medium for the full publication of results of this kind. Would it be amiss for the Division of Chemical Education to outline a definite program in this matter? If the meetings were conducted in part as a series of symposiums on specific problems we might hope to bring to light an abundance of good ideas that would otherwise stay at home. The most important need, however, is that the individual teacher shall be impressed with the value of research in chemical education. It is a field where everyone may take a hand.

Which shall it be, Ruts or Research?

G. H. CARTLEDGE.

QUALITATIVE ANALYSIS WITHOUT HYDROGEN SULFIDE R. D. MULLINIX, Rockford College, ROCKFORD, ILL.

I began to investigate the possibilities of a system of analysis without hydrogen sulfide something over three years ago, before I knew that anyone had considered the subject seriously. For a time I used a simplified method in which only a few of the most familiar metals were tested for. The scheme was used during the latter part of the first year chemistry to make more interesting the study of the metals. Hydrogen sulfide is such a disagreeable substance, especially the way general chemistry students use it, in laboratories not well provided with hoods, that I decided to extend my simplified system to all the common metal ions and to compare its sensitiveness with that of the usual method in which hydrogen sulfide is the precipitating agent.

Almkvist' at Stockholm in 1918 had developed a method in which the precipitating agent was a mixture of sodium carbonate and sodium hydroxide, and had in addition done some work on the solubilities of certain hydroxides, namely those of manganese, nickel, cobalt and ferric iron1. But, although Almkvist avoided the use of hydrogen sulfide he used, later on in the course of the analysis, sodium sulfide and then added sulfuric acid. This procedure would of course require the use of a hood. He also used a distillation method to determine the arsenic and antimony. Such distillation methods are usually slow and seldom lead to a complete separation. The well known method for acid ions by A. A. Noyes is an illustration of such a system. Almkvist's distillation method makes a partial separation of the antimony, that is, antimony must be tested for in the residue and in the distillate.

When we consider the solubilities of the hydroxides and carbonates of the common metals we find that they are small and compare well with the values of the solubilities of the sulfides of these elements. We can also use high concentrations of the hydroxide and carbonate ions. The hydrated dioxide of manganese is indeed less soluble than the sulfide, in which form it is usually precipitated, and copper oxide is about as insoluble as copper sulfide. Also, we know that the hydroxides of nickel and cobalt are considered sufficiently insoluble to be used to remove these ions in the ordinary system of analysis before zinc is precipitated as sulfide.

It is not necessary to have a system of analysis that is of the greatest possible delicacy, since we are using the thing not to analyze mixtures so much as to teach the principles of chemistry. The hydroxide and carbonates are insoluble enough to be used to detect smaller "traces" that are usually put in any "unknown." If we were after the most delicate tests we could use the Marsh or some such test for arsenic and the Nessler test for ammonia. 1 Z. fur anorg. Chem. 103, 221 (1918).

We are using analytical methods to teach general relations and not to detect the smallest possible traces of ions. We might as well, therefore, have a method that can be used from start to finish on an open desk in the laboratory. It is not necessary to point out that the solubility product, principle, amphoteric hydroxide complex ions, group separations, etc., can be developed with hydroxides and carbonates as well as with sulfides. By using such a method at the end of general chemistry the student who later studies the regular qualitative courses where hydrogen sulfide is the precipitating agent will have a broader experience from which to draw for guidance in solving the many problems of analytical work.

The silver group is precipitated as usual by the addition of hydrochloric acid. The analysis of this group follows the scheme now used by all authors. From the filtrate all other ions except those of sodium, potassium, and the amphoteric hydroxides, arsenic, antimony, tin, aluminium, zinc, and chromium are precipitated by a mixture of sodium hydroxide, sodium carbonate and an oxidizer such as bromine water or hydrogen peroxide. The chromium is oxidized to chromate and the manganese to a valence of four. The precipitate, thoroughly washed, is treated with a small excess of nitric acid. Manganese dioxide is left as a residue. Excess of ammonium hydroxide added to the nitric acid filtrate will precipitate all the bismuth and iron. From the ammoniacal filtrate ammonium carbonate will precipitate barium, calcium and strontium. Analyze this precipitate in the usual manner. The magnesium in the filtrate is removed by sodium phosphate.

If the unknown contains phosphate, the alkaline earth group will precipitate with the bismuth and iron unless the phosphate is taken care of by ferric chloride as is done in other systems of analysis.

The filtrate from the magnesium contains copper, cadmium, nickel, cobalt, and mercuric mercury. Mercury is tested for and removed with stannous chloride (a very satisfactory separation) and the cadmium brought down by sodium sulfide in the presence of sodium hydroxide and potassium cyanide. The added tin will not precipitate. A portion of the filtrate from the magnesium (after the removal of mercury) is tested for copper by means of acetic acid and potassium ferrocyanide; a portion for nickel by the dimethylglyoxime test and another portion for cobalt by means of alpha nitroso beta napthol. The tin does not interfere with the tests for nickel and cobalt.

The first filtrate containing the amphoteric ions is acidified with nitric acid. A test for chromate is made on a portion of this nitric acid solution and, if chromate is not present, a few drops of sodium chromate are added to precipitate the trace of lead that may be present. The nitric acid solution is made alkaline with ammonium hydroxide, and a drop of sulfuric acid is added to precipitate the trace of lead that may be present. The