J76 Mr, Stephens's Suggestions of the Improvement [Nov. 



— like a gentleman called on to explain what he knows on an 

 interesting subject to a company of his friends, he may be 

 almost certain of success. 



In imparting a knowledge of this science, a speaker has vast" 

 advantages over an author. The illustrations of books are 

 limited to drawings ; whilst in conversation a teacher can add 

 to these expejrimental exhibitions and specimens which enable 

 all the senses to aid in fixing an association of ideas in the 

 memory. He can employ emphasis or gesture, repeat or omit 

 particular facts, refine or lower his style as may appear proper. 

 His mere glance awakens attention. He can explain, if it 

 appear he has been previously misunderstood, bring forward 

 the latest and most interesting facts applicable to his subject, 

 and make even accident the ground of pleasing and instructive 

 remark. It therefore requires no great depth of observation to 

 enable a lecturer to determine which of the two systems, writing 

 or speaking, he should incline to, and cultivate. 



One of the greatest advantages which a chemical lecturer 



may avail himself of, is that of conversing with his class after 



lecture; and fortunately the benefits are reciprocal. He is 



\llovved an opportunity of coming at their difficulties, answer- 



ng objections, and removing misunderstandings by simplifying 



he subject. A single misconception at the beginning of a 



ecture is often sufficient to prevent a pupil comprehending 



v^hat follows, yet it is impossible at the time for a lecturer to 



lenetrate and remove the cause of his embarrassment. He 



»ught therefore to invite regular explanatory conversations with 



he class for his own sake as well as theirs, for it cannot be 



reditable to a teacher to be incomprehensible to any of his 



mpils. 



When the children of operatives form a portion of his class, 

 ommunication on both sides is still more necessary. As it 

 eveals to him their peculiar deficiencies, he will perceive the 

 ropriety (indeed the necessity) of explaining more than 

 trictly belongs to his own science to render it fully understood, 

 'hey generally hear local names and terms of art widely diffe- 

 mt from the scientific phraseology, but which nevertheless a 

 icturer must make himself master of, to become intelligible : 

 I fact, he nuist translate his words into theirs as he goes on. 

 /hen he speaks of elements, their thoughts are perhaps fixed 

 n fire, air, earth, and water, which still maintain that rank in 

 )me of their school-books ; salt conveys only the idea of the 

 alinary variety, and salts (in their conception of the term) is 

 istricted to the pharmaceutical preparations of Cheltenham, 

 .ochelle, Epsom, &c. Gas will most likely be limited to our com- 

 jon source of illumination ; spirit is generally used to designate 

 ny acid employed in the arts; metal is understood in different 

 inses by the iron-founder, the brazier, the glass-blower, and the 



