AUTHORITIES EMPLOYED IN PREPARING THE LECTURES. 109 



five classes (each occupying an hour) every day, except 

 Sundays, in addition to the Lecture given on five days of the 

 week; and, at Hazelwood, the number of hours daily occu- 

 pied in actual instruction has been, uniformly, still greater. 

 Extensive collections of materials for the Lectures and a 

 rigorous scrutiny of them, being therefore impossible, it be- 

 came necessary to select and employ the best authorities, 

 from which the instruction to be imparted might be derived. 

 In the preparation of the Lectures on the Supporters of Com- 

 bustion and the Combustibles, the principal authorities em- 

 ployed, were, the second edition of Mr. Brande's Manual of 

 Chemistry, the second edition of Dr. Turner's Elements of 

 Chemistry, and Sir H. Davy's Elements of Chemical Philo- 

 sophy. I have in general united the detail of facts as given 

 by Dr. Turner, with the arrangement of Mr. Brande : Sir H. 

 Davy's Elements, although not perhaps the most perfect or the 

 most valuable production of its illustrious author, was yet 

 admirably adapted for the purpose I had in view, as well by 

 the elevation of the philosophic spirit which pervades it, as by 

 the simplicity and elegance of the statements it contains ; for 

 I have uniformly found, that the most profoundly philosophical 

 views of the laws of nature, when properly explained and ex- 

 panded into detail, are the best adapted for the comprehension 

 of the young mind, and indeed for that of learners in general. 



In the preparation of the Lectures on Vegetable and Animal 

 Chemistry, the same authorities were used, with the addition 

 of Sir H. Davy's Elements of Agricultural Chemistry, which 

 is perhaps one of the most perfect works, on a particular depart- 

 ment of a science, that has ever been produced, uniting com- 

 prehensive philosophic views with great accuracy of detail, 

 and a just and beautiful application of the principles of Che- 

 mical science to the practice of the arts of Cultivation. I also 

 endeavoured to bear in mind, throughout the preparation of 

 this Course, the views partially developed by Dr. Prout, in his 

 paper on the ultimate composition of simple alimentary sub- 

 stances, published in the Philosophical Transactions for 1827, 

 to which I constantly referred, when treating of any of the 

 subjects mentioned in it. Dr. Paris' s Medical Chemistry, the 

 notes accompanying Mr. Phillips's Translation of the Phar- 

 macopoeia of the Royal College of Physicians of London, Sir 

 James E. Smith's Introduction to Physiological and Systematic 

 Botany, and Dr. Fleming's Philosophy of Zoology, have fur- 

 nished me with some information, on subjects particularly 

 treated of in those works. 



I have endeavoured, in the preparation or delivery of all my 

 instructions, to unite with the statements derived from the au- 



