PREFACE. 11 ; 



made a business of popular lecturing. In such cases, how- 1 

 ever, the instruction offered to the audience was but a shade ! 

 better than that afforded by the amateurs to whom I have just 

 referred. The information of these teachers is usually but 

 skin deep. Their study, if so it can be called, is made ex- 

 pressly for their lectures, and the measure of their own infor- 

 mation is strictly limited by the demands of their audience. 

 They have learned for the occasion so much about the matter 

 in hand as they shall have to say, and no more. Like certain 

 storekeepers in Broadway and Chesnut-street, they exhibit 

 their entire stock in their windows. 



Although such was the general character of the popular 

 lectures given in the chief cities at the time to which I refer, 

 there were, nevertheless, occasional exceptions. Public 

 teachers, eminently qualified, were from time to time induced 

 to extend the benefits of their labors from the professional 

 chairs of the universities, colleges, and public schools, to the 

 more mixed and popular assemblies of the literary societies of 

 the towns and cities of the Union, or to deliver courses to 

 classes brought together by the talents and reputation of the 

 lecturer. In such case, I observed that the superior value of 

 the instruction offered was duly appreciated by the public, and 

 that large and attentive audiences were collected, notwith- 

 standing the unavoidable imposition of a much higher fee of 

 admission. 



Encouraged by all these circumstances, I proceeded to pre- 

 pare the necsssary means of illustration adapted for large and 

 popular audiences, and commenced my proceedings by a 

 public lecture given in the lecture-room of Clinton-Hall, in 

 New York, in November, 1841. The result having proved to 

 be successful, I removed to the theatre at Niblo's gardens, \ 

 where an advantageous arrangement was made with the pro- ! 



