Organization of second-year course
The work of the second year of chemistry in college generally consists of quantitative analysis, though the more intensive study of the compounds of carbon, known as organic chemistry, is also frequently taken up at this time, and there is much to be said in favor of such practice.
Content of the course in quantitative analysis
In the quantitative analysis, habits of neatness and accuracy must be insisted upon. It is well to give the general orientation and directions by means of lectures. One or two such exercises per week will suffice. There should also be recitations. When two lectures per week are given, it will suffice to review the work with the student in connection with such lectures, provided the class is not too large for quiz purposes. Intelligent work should characterize a course in quantitative analysis. To this end the student should be taught how to take proper representative samples of the material to be analyzed. He should then be taught how to weigh or measure out that sample with proper care. The manipulations of the analytical process should be carried out so that each step is properly understood and its relations to the general laws of chemistry are constantly before the mind. In carrying out the process, the various sources of error must be thoroughly appreciated and guarded against. The final weighing or measuring of the form in which the ingredient sought is estimated should again be carried out with care, and in the calculation of the percentage content due regard should be had for the limits of error of experimentation throughout the entire analytical process. The student feels that a large number of the exercises in quantitative analysis are virtually cases of making chemical preparations of the highest possible purity, thus connecting his previous chemical experience with his quantitative work. The course in quantitative analysis should cover the determination of the more important basic and acid radicals, and should consist of both gravimetric and volumetric exercises.
The choice of the exercises is of great importance. It may vary, and should vary considerably in different cases. Thus a student in agriculture is naturally interested in the methods of estimating lime, phosphorus, nitrogen, potash, silica, sulphur, etc., whereas a student in engineering would be more interested in work with the heavy metals and the ingredients which the commercial samples of such metals are apt to contain. Thus, analytical work on solder, bearing metal, iron and steel, cement, etc., should be introduced as soon as the student in engineering is ready for it. It is quite possible to inculcate the principles of quantitative analysis by selecting exercises in which the individual student is interested, though, to be sure, certain fundamental things would naturally have to be taken by all students, whatever be the line for which they are training. A few exercises in gas analysis and also water analysis should be given in every good course in quantitative analysis that occupies an entire year. Careful attention should be given to the notebook in the quantitative work, and the student should also be made to feel that in modern quantitative analysis not only balances and burettes are to serve as the measuring instruments, but that the polariscope and the refractometer also are very important, and that at times still other physical instruments like the spectroscope, the electrometer, and the viscometer may prove very useful indeed.
The quantitative analysis offers a splendid opportunity for bringing home to the student what he has learned in the work of the first year, showing him one phase of the application of that knowledge and making him feel, as it were, the quantitative side of science. This latter view can be imparted only to a limited degree in the first year's work, but the quantitative course offers an unusual opportunity for giving the student an application of the fundamental quantitative laws which govern all chemical processes. It is not possible to analyze very many substances during any college course in quantitative analysis. The wise teacher will choose the substances to be analyzed so as to keep up the interest of the student and yet at the same time give him examples of all the fundamental cases that are commonly met in the practice of analytical work. A careful, painstaking, intelligent worker should be the result of the course in quantitative analysis. Toward the end of the course, too, a certain amount of speed should be insisted upon. The student should be taught to carry on several processes at the same time, but care should be taken not to overdo this.
The course in organic chemistry
In the course in organic chemistry, lectures, laboratory work, and recitations, arranged very much as to time as in the first year, will be found advantageous. If the intensive work in organic chemistry is postponed to the third year in college, there are certain advantages. For example, the student is more mature and has had drill and experience in the somewhat simpler processes commonly taught in general and analytical chemistry. On the other hand, the postponing of organic chemistry to the third year has the disadvantage that the student goes through his basal training in quantitative analysis without the help of that larger horizon which can come to him only through the study of the methods of organic chemistry. The general work of the first year, to be sure, if well done compensates in part for what is lost by postponing organic chemistry till the third year, but it can never entirely remove the loss to the student. Teachers will differ as to whether the time-honored division of organic chemistry into the aliphatic and aromatic series should be maintained pedagogically, but they will doubtless all agree that the methods of working out the structure of the chemical compound are peculiarly characteristic of the study of the compounds of carbon, and these methods must consequently constitute an important point to be inculcated in organic chemistry. The derivation of the various types of organic compounds from the fundamental hydrocarbons as well as from one another, and the characteristic reactions of each of these fundamental forms which lead to their identification and also often serve as a means of their purification, should naturally be taught in a thoroughgoing manner. The numerous practical applications which the teacher of organic chemistry has at his command will always serve to make this subject one of the deepest interest, if not the most fascinating portion of the entire subject of chemistry. No student should leave the course in organic chemistry without feeling the beautiful unity and logical relationship which obtains in the case of the compounds of carbon, the experimental study of which has cast so much light upon the chemical processes in living plants and animals, processes upon which life itself depends. The analysis of organic compounds is probably best taught in connection with the course in organic chemistry. It is here that the student is introduced to the use of the combustion furnace and the method of working out the empirical formulæ of the compounds which he has carefully prepared and purified. The laboratory practice in organic chemistry generally requires the use of larger pieces of apparatus. Some of the experiments also are connected with peculiar dangers of their own. These facts require that the student should not approach the course without sufficient preliminary training. Furthermore, the teacher needs to exercise special care in supervising the laboratory work so as to guard the student against serious accidents.
The historical development of organic chemistry is especially interesting, and allusions to the history of the important discoveries and developments of ideas in organic chemistry should be used to stimulate interest and so enhance the value of the work of the student. The practical side of organic chemistry should never be lost sight of for a moment, and under no condition should the course be allowed to deteriorate into one of mere picturing of structural formulæ on the blackboard. All chemical formulas are merely compact forms of expression of what we know about chemical compounds. There are, no doubt, many facts about chemical compounds which their accepted formulas do not express at all, and the wise teacher should lead the student to see this. There is peculiar danger in the course in organic chemistry that the pupil become a mere formula worshiper, and this must carefully be guarded against.
The applications of organic chemistry to the arts and industries, but especially to biochemistry, will no doubt interest many members of the class of a course in organic chemistry if the subject is properly taught. This will be particularly the case if the teacher always holds before the mind of the pupil the actual realities in the laboratory and in nature, using formulation merely as the expression of our knowledge and not as an end in itself.