ON TEACHING CHEMISTRY. 85 



-combining with or displacing one another. I should like to see some 

 encouragement given to the historical aspects of chemistry. I have 

 found that explanations of when and how the chief elements, acids 

 and alkalies came to be known add much to an intelligent interest in the 

 subject.' 



LXII. ' It has always appeared desirable that a boy should approach 

 <!hemistry in the same way that all the founders and builders-up of the 

 science have done : viz., not by first reading a printed account of facts 

 ■and then verifying them or seeing them verified, but by studying the 

 different forms of matter as substances hitherto unknown, the properties 

 of which have to be investigated for the first time and compared with 

 those of other substances. With this view the experiments shown are 

 considered as questions put to Nature, the answers to which are as little 

 known to the lecturer as to the learners. No predictions are made as to 

 the results, although boys are not unfrequently asked what, arguing from 

 -experiments previously shown or the properties of analogous substances 

 previously examined, may be expected to occur. All apparatus used is 

 -described ; the reasons for any special arrangement of it being explained 

 fully. Elaborate forms of apparatus with a profusion of drying tubes, 

 Woulf's bottles, fantastically bent leading-tabes, are avoided as far as 

 possible, their tendency being to draw off attention from the main point 

 of the experiment. The arithmetical side of chemistry is not very much 

 ■enlarged upon ; it seems hardly desirable that boys should look upon 

 experiments as pegs on which numerical problems ai'e to be hung. Too 

 much time may easily be spent in elaborate calculations on the quantity 

 of zinc required to obtain enough hydrogen to decompose the nitrogen 

 monoxide produced fi-om ten grammes of ammonium nitrate. Innumer- 

 able examples, however, illustrative of important laws, such as those of 

 Gay-Lnssac and Avogadro, and of calculations actually required in 

 quantitative work, are frequently set, generally at the beginnino- of each 

 lecture, in reference to some point explained in the preceding one. No 

 symbols, formulae, or equations are used at first — not, in fact, until the 

 properties of three or four elements, and of some of their compounds, 

 have been studied and the laws of chemical combination deduced from 

 them. Then, and not till then, it is thought that a learner can appreciate 

 the value of Dalton's atomic theory in accoanting for the facts he has 

 observed, and can see the advantage of a system of chemical shorthand, 

 and use it with intelligence and discrimination.' 



LXIII. ' The method, in my opinion, most likely to render the teaching 

 effective as a mental discipline is mercilessly to sweep off a large pro- 

 portion of the facts at present dealt with, to confine the attention of the 

 pupil to those that for various reasons are the most important, and to use 

 them always as illustrations of general laws. For this purpose, there must 

 be agreement among teachers and examiners. I do not think it beyond 

 the scope of your inquiry to suggest that, to make chemistry or any 

 matural science do all that it can do towards mental discipline, there must 

 be an attempt to use it as a means of destroying the contempt which 

 familiarity breeds in us all towards common things. Unless you can call 

 forth the interest of your pupil, his admiration, even his reverential awe 

 towards the mystery of Nature, you have perhaps done more harm than 

 good.' 



LXIV. ' Eternal analyses of simple salts and mixtures such as are 

 required by examinations of the present day weary and worry the student, 



