IV PKEFACE. 



rules have been adopted ; the first is, to print no oral com- 

 munications unless furnished or revised by the Author him- 

 self. In the former volume this rule was slightly deviated 

 from, for the purpose of showing in what manner the 

 Meetings were conducted. But however valuable a part of 

 the proceedings of the Meetings the verbal communications 

 and discussions maybe, it is evidently impossible to publish 

 a safe and satisfactory report of them from any minutes 

 which can be taken. The second rule is, not to print any 

 of the miscellaneous communications at length ; but either 

 abstracts of them, or notices* only, the object of the rule 

 being to keep the Transactions within the bounds which 

 the Association has prescribed to itself, and to prevent any 

 interference with the publications of other societies. In 

 the present volume, there is one paper printed at lengthf , 

 which contains the results of certain experiments instituted 

 expressly at the request of the Association. 



The Recommendations of various subjects for scientific 

 inquiry agreed upon at Cambridge have been here incor- 

 porated with those adopted at former Meetings, and the 

 Suggestions which are contained in the Reports on the state 

 of science, published in the present and preceding volume, 

 have likewise been added; so as to present a general view of 

 the desiderata in science to which attention has been invited. 

 To this part of the volume are also appended those direc- 

 tions for the use of observers which have proceeded from 

 Committees appointed to promote particular investigations. 



To the Transactions is prefixed a brief outline of the 

 General Proceedings of the Cambridge Meeting, a fuller Rc; 

 port of them having been rendered unnecessary by the ac- 

 count which has already issued from the University press. 

 The observations, however, delivered by the Rev. Mr. Whe- 

 WELL on the state of science as it is exhibited in the first 

 volume of the Reports of the Association, not having been 

 before published, are printed at length. 



• The notices of Communications will be found in the general account of the 

 Proceedings of the Sections, p. 353. 



f " Experiments on the Quantity of Rain which falls at different Heights in 

 the Atmosphere." 



