Nov. 6, 1884] 



NA TURE 



distinction between elements and compounds ; the fundamental 

 laws which regulate the formation of compounds and the chemical 

 action of bodies upon one another (i.e. the nature of so-called 

 chemical change) ; the chemical properties of the metals in 

 ordinary use, with spi rial reference to their uses and the action 

 upon them of air, water, &c. ; the composition of natural waters ; 

 \ tween fats, carbohydrates and albuminous sub- 



stances in isential to the understanding of the relative 



values of different foods and respiration and growth in animals 

 and plants (outlines of the chemistry of animal and plant life, in 

 fact) ; the nature of the processes of fermentation, putrefaction, 

 and deca) . 



The instruction in these subjects should in all cases ne im- 

 parted by means of object-lessons and tutorial classes ; lectures 

 pure and simple should, as far as possible, be avoided. The 

 Students should by themselves go through a number of practical 

 exercises on the various subjects. I would abolish the teaching 

 of tables for the detection of simple salts, the teaching of analy- 

 sis as at present conducted being, I believe, in most cases of 

 very little if any use except as enabling teachers to earn grants. 



In schools and colleges in which chemistry is taught as a 

 science, and ostensibly with the object of training young people 

 to be chemists, it is the almost invariable practice that the 

 student first devotes more or less time to the preparation of the 

 commoner gases, and then proceeds to study qualitative analysis ; 

 quantitative determinations are made only during the later period 

 of the course. I believe that the system has two great faults : it 

 is too mechanical, and does not sufficiently develop the faculty 

 of reasoning from observation ; and actual practice in measure- 

 ment is introduced far too late in the course. It is of great im- 

 portance that the meaning of the terms equivalent, atomic 

 weight, molecular weight, should be thoroughly grasped at an 

 early stage, but according to my experience this is very rarely 

 the case ; there is no such difficulty, however, if the beginner is 

 taught to make a few determinations himself of equivalents, &c. , 

 as he very well may be. It is not necessary here to enter into 

 a more detailed criticism, but I propose instead to give a brief 

 description of a modification of the existing system which in my 

 hands, in the course of about four years' experience, has fur- 

 nished most encouraging results, and which I venture to think 

 is worthy of an extended trial. 



Instead of merely preparing a variety of gases, the student is 

 required to solve a number of problems experimentally : to 

 determine, for example, the composition of air and of water ; 

 and the idea of measurement is introduced from the very 

 beginning, as the determination is made quantitatively as well 

 as qualitatively. Each student receives a paper of instructions 

 — two of which are printed as an appendix to this paper — which 

 are advisedly made as bare as possible so as to lead him to find 

 out for himself, or inquire, how to set to work ; and he is par- 

 ticularly directed that, having made an experiment, he is to enter 

 in his notebook an account of what he has done and of the 

 result, and that he is then and there to ask himself what bearing 

 the result has upon the particular problem under consideration, 

 and, lnvmg done so, he is to write down his conclusion. He is 

 thus at once led to consider what each experiment teaches : in 

 oilier words, to reason from observation. Apart from the 

 mental exercise which this system affords, if the writing out of 

 the notes be properly supervised, the literary exercise which it 

 also affords is of no mean value. 



In illustration, I may here very briefly describe the manner 

 of working out the second problem in the course. The problem 

 being to determine the composition of water, the student 

 ruction : — 1. Pass steam over red-hot iron brads, 

 collect the escaping gas, and apply a light to it. (N.B. The 

 gas thus produced is called hydrogen.) He is provided with a 

 very simple apparatus, consisting of a small gla-s flask contain- 

 ing water, joined by a narrow bent glass tube to an iron tube 

 (about 9 inches long and -h to 5 inch wide) in which the brads 

 I, a long glass tube suitably bent for the delivery of the 

 gas being attached to the other end of the iron tube. Plaster 

 of Paris i used instead of corks to make the connections with 

 the iron tube. The iron tube is supported over a burner, and 

 heated to redness ; the water in the flask is then heated to 

 boiling, and the steam thus generated is passed over the brads ; 

 (he escaping gas is collected over water in the usual manner. 

 Having made this experiment, and observed that, on passing 

 steam over red-hot iron, the gas hydrogen is produced, the 

 student proceeds to consider the bearing of this observation. 

 The hydrogen must obviously be derived either from the water 



or from the iron, if not from both. Those who already know 

 that iron is iron, so to speak, at once infer that the hydrogen is 

 derived from the water : it is, however, pointed out that, even if 

 it be known that iron is a simple substance, this observation 

 taken alone does not prove that hydrogen is contained in water. 



2. The student next learns to prepare hydrogen by the ordin- 

 ary method of dissolving zinc in diluted sulphuric acid, and 

 makes a few simple experiments whereby he becomes acquainted 

 with the chief properties of the gas. 



3. Having done this, he is instructed " to burn dry hydrogen 

 at a glass jet underneath a cold surface and to collect and exa- 

 mine the product." The product is easily recognised as water, 

 and the immediate answer to the question, "What does this 

 observation teach ? " is, that since iron is absent, taken in con- 

 junction with Experiment 1, the production of water on burning 

 hydrogen in air, the composition of which has already been 

 determined, is an absolute demonstration that hydrogen is con- 

 tained in water. 



4. Having previously studied the combustion of copper, iron, 

 and phosphorus in air, and having learnt that when these sub- 

 stances burn they enter into combination with the oxygen in air, 

 the student is also led to infer from the observation that hydro- 

 gen burns in air producing water, that most probably it combines 

 with the oxygen, and that water contains oxygen besides hydro- 

 gen. It may be however, it is then pointed out, that the 

 hydrogen, unlike the phosphorus, &c. , combines with the nitro- 

 gen instead of with the oxygen, or perhaps with both. He is 

 therefore instructed to pass oxygen overheated copper, weighing 

 the tube before and after the operation, and subsequently to heat 

 the "oxide of copper" in a current of hydrogen. He then 

 observes that water is formed, the oxygen being removed from 

 the copper : and since nitrogen is absent, it follows that water 

 consists of hydrogen and oxygen, and of these alone. 



5. By repeating this last experiment so as to ascertain the loss 

 in weight of the copper oxide tube and the weight of water 

 produced, the data are obtained for calculating the proportions 

 in which hydrogen and oxygen are associated in water. 



In practice the only serious difficulty met with has been to 

 induce students to give themselves the trouble to consider what 

 information is gained from a particular observation ; to be pro- 

 perly inquisitive, in fact. I cannot think that this arises, as a 

 rule, from mental incapacity. When we consider how the child 

 is always putting questions, and that nothing is more beautifully 

 characteristic of young children than the desire to know the why 

 and wherefore of everything they see, I fear there can be little 

 doubt that it is one of the main results — and it is indeed a 

 lamentable result — of our present school system that the natural 

 spirit of inquiry, inherent to a greater or less extent in every 

 member of the community, should be thus stunted in its growth, 

 instead of being carefully developed and properly directed. 



Having in the manner which I have described studied air, 

 water, the gas given off" on heating common salt with sulphuric 

 acid, and the ordinary phenomena of combustion, the student 

 next receives a paper with directions for the comparative study 

 of lead and silver (see Appendix). The experiments are chosen 

 so as to afford an insight into the principles of the methods 

 ordinarily employed in qualitative and quantitative analyses, and 

 the student who has conscientiously performed all the exercises 

 is in a position to specialise his studies in whatever, direction 

 may be desirable. 



The system I have thus advocated undoubtedly involves far 

 more trouble to the teacher than that ordinarily followed, but 

 the student learns far more under it, and I assert with confidence 

 that the training is of a far higher order, and also of a more 

 directly useful character. I believe it to be generally applicable, 

 and that it would be of special advantage in those oases in which 

 only a short time can be devoted to the study of chemistry, as 

 in evening classes and medical schools. At present the only 

 practical teaching vouchsafed to the majority of students in our 

 large medical schools is a short summer course, during which 

 they are taught the use of certain analytical tables : as a mental 

 exercise the training they receive is of doubtful value ; the know- 

 ledge gained is of little use in after life, and the course certainly 

 ought not to be dignified by being spoken of as a course of 

 Practical Chemistry ; test-tubing is the proper appellation. It is 

 not a little remarkable also that even the London University 

 Syllabus nowhere specifies that a knowledge even of the elements 

 of quantitative analysis will be required of candidates either at 

 the Preliminary Scientific or First M.B. Examination, and this, 

 too, when, as is well known, an analysis to be of any practical 



