372 Mr. Stephens*s Suggestions for the Improvement [Nov, 



substances which together form the compound that the lecturer 

 is speaking of, they will have comparatively little difficulty in 

 recollecting the composition of bodies. No actual preparation 

 of the elementary substances should be attempted before a 

 class of beginners, for they are not prepared to understand the 

 rationale ot their production. This exhibition should be re- 

 served for another course, and for another class who are suffi- 

 ciently advanced to comprehend the means by which the lec- 

 turer obtains them, and are in no danger of supposing that he 

 is making hydrogen or oxygen gas, when he is only liberating it. 



In fact, this science is so extensive, and so peculiarly liable 

 to misconception in its language and objects, that two distinct 

 courses are indispensibly requisite to avoid inconsistency and 

 confusion, and enable a teacher to do justice to his class. The 

 first, — simple, explanatory, synthetic, — ascending from elements 

 to compounds, and so arranged that the class may arrive at a 

 knowledge of the laws of nature as the result of direct experi- 

 ments. Here the lecturer should address his auditors as persons 

 totally ignorant of chemistry. This course ought to be prepa- 

 ratory to the second, wherein he might proceed on the present 

 system; that is, — first promulgating general laws, and then 

 illustrating them by exhibitions and experiments ; and so far 

 as the previous lectures had made his class acquainted with the 

 substances experimented upon, so far will they really understand 

 and profit by these. 



The latter may be termed the descending, the analytic lec- 

 tures, in which the decomposition of substances might be expe- 

 rimentally pushed to the utmost limits of our skill, the methods 

 of detection and separation thoroughly explained, and the ap- 

 plication of chemistry to the arts and manufactures ; to phar- 

 macy, metallurgy, agriculture, &c. demonstrated with all the 

 eloquence and collateral information which can be brought to 

 bear upon the subject. The refinements of electricity, magne- 

 tism, may now be displayed with consistency and effect ; and a 

 discussion of the principal conflicting speculations which divide 

 the chemical world may also be intelligibly entered on. By 

 these arrangements, all who are prepared to enjoy the heights 

 of science may be gratified without the loss of time they have 

 hitherto sustained in listening to a repetition of well known 

 facts, (which the present mixed system renders unavoidable) ; 

 and those who now sit year after year endeavouring to under- 

 stand the subject, will also be enabled (by the preparatory 

 course) to derive enjoyment and instruction from elevated 

 themes, which would otherwise be to them the essence of per- 

 plexity. 



In the elementary lectures, the various substances should be 

 arranged as much as possible into the distinct and famihar 

 groups which the pupil's mind would naturally place them in. 



