PREFACE. 



The Transactions of the British Association consist of 

 three parts ; first, of Reports on the State of Science drawn 

 up at the instance of the Association ; secondly, of Miscel- 

 laneous Communications to the Meetings ; and thirdly, of 

 Recommendations by the Committees, having for their ob- 

 jects to mark out certain points for scientific inquiry. 



It is proper to remark, that some of the Reports here 

 printed are to be considered in the light of first parts of 

 the intended survey of the sciences reviewed in them, the 

 continuation being postponed to a future Meeting. Thus, 

 the Report on Hydraulics, by Mr. G. Rennie, will be 

 completed in a second part, to be presented to the Meeting 

 at Edinburgh ; the Report on the mathematical theory of 

 the same science, by the Rev. Mr. Challis, which is 

 here restricted to problems on the common theory of Fluids, 

 will be further extended to the theories which have recently 

 been advanced respecting the internal constitution of Fluids 

 and the state of their caloric, to account for certain phseno- 

 mena of their equiUbrium and motion ; and the Report on 

 Analytical Science, by the Rev. Mr. Peacock, which in the 

 present volume includes Algebra, and the application of 

 Algebra to Geometry, is intended to be hereafter concluded 

 by a review of the Diiferential and Integral Calculus and the 

 theory of Series. In like manner, to the Report on Botany, 

 by Dr. Lindley, which embraces only the physiological 

 part of the science, that which Mr. Bentham has under- 

 taken on the State and Progress of Systematic Botany will 

 be supplemental ; and to the present Report, by Dr. Charles 

 Henry, on one branch of Animal Physiology, a more 

 general review of the progress of that science will be added 

 by the Rev. Dr. Clark. 



With respect to the next part of the Transactions, which 

 includes the communications made to the Sections, two 



a 2 



