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PREFACE. 17 



lar lecturer, both in Europe and America. I may therefore < 

 be allowed to express a hope, that this statement may prove 

 useful to others who may be induced to adopt a like course 

 with the same public object. 



The misce laneous nature of the contents of the present 

 volumes, and the absence of any logical connexion or ar- 

 rangement among them, render some further explanation ne- 

 cessary respecting the mode in which the lectures were given. 

 The audiences being composed, for the most part, of persons 

 engaged in the pursuits of business, the exercise of profes- 

 sions, and the other active occupations of life, no regular cr 

 consecutive attendance on any series of lectures could be 

 looked for. Occasional attendances, as leisure, convenience, 

 or inclination, might induce, were all that could be expected. 

 It was, therefore, necessary that the discourses delivered on 

 each evening should be, as far as possible, separate and inde- 

 pendent, intelligible, useful, and entertaining of themselves, 

 without reference to any others previously given, so that no 

 one might be deterred from availing themselves of any one 

 evening's lecture merely because they had not been enabled 

 to attend the preceding ones. The same consideration ren- 

 dered it unnecessary to observe any fixed order in the subjects 

 of the lectures. It was usual to extend the evening's enter- 



O 



tainment to a length not previously customary with public 

 lectures. From two and one half to three hours was not an 

 unusual length. This time, however, was not devoted to a 

 single subject. A succession of two, three, and sometimes 

 four subjects, would often be produced, having no connexion 

 whatever with each other. Thus astronomy, electricity, and I 

 the steam-engine, would be successively noticed, short inter- j 

 vals of rest being left between them, as between the perform- I 



ances in a dramatic theatre. Unusual and unpromising as 

 VOL. i. a 



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