THE SMITHSONIAN INSTITUTION. 217 



journals, so that in the course of a few years another report of a simi- 

 lar kind, or one which ma}^ be considered a continuation of this, can 

 be published. 



Copies, at the mere cost of printing, paper, and commission, are 

 offered for sale. The matter has been stereotyped, in order to supply 

 all the demand, and to reproduce this member of the series, should the 

 subject be continued. 



The progress of the elaborate report on the Forest-trees of North Ameri- 

 ca, mentioned in the last two Reports, was for some time arrested by 

 the absence of the author, Dr. Gray, in Europe. He has now, how- 

 ever, returned, and will resume the preparation of the drawings, as 

 soon as the funds of the Institution will admit of the expenditure. This 

 work has proved a more expensive undertaking than was at first anti- 

 cipated, and can only be finished on the original plan, by extending the 

 time of its publication over several years. It will form a valuable 

 contribution to the botany and economical and ornamental arts of our 

 country. 



Dr. F. G. Melsheimer, of Dover, Pennsylvania, has presented to the 

 Institution a catalogue of the coleopterous insects of North America, 

 with references to the principal places of description. This has been 

 put to press, but progresses slowly on account of the great care 

 necessary in correcting the proofs. When prmted, it will be of great 

 service to the cause of American entomology. 



Besides the reports, other works are in progress, among which may 

 be mentioned a small volume by Professor Baird, consisting of practi- 

 cal directions for the collection and preservation of specimens of natural 

 history. This will be illustrated with numerous figures, and issued as 

 soon as the engravings can be procured. A part of the letter-press has 

 been finished. It is especially designed for the use of travellers and 

 officers of the arm}^ and navy who may be inclined to make collections 

 for the Smithsonian Institution, but will be of general interest to the 

 cultivators of natural history. 



A volume of tables of use in meteorology and other branches of 

 scientific observations, has been prepared, under the direction and at 

 the expense of the Institution, by Professor Arnold Guyot. The follow- 

 ing are the contents of this volume, viz : 



1. Thermometrical tables for the conversion of the scales of different 

 thermometers into each other. 



2. Hygrometrical tables giving the elastic force of vapor, the relative 

 humidit}", &c. 



3. Barometrical tables for the comparisons of different scales, reduc- 

 tion of observations to the freezing-point, and correction for capillary 

 action. 



4. Hypsometrical tables for calculating altitudes by the barometer, 

 and by the difference of the boiling-point. 



5. Tables of the corrections to be applied to the monthly means to 

 obtain the true mean. 



' 6. A set of miscellaneous tables frequently required in physical inves- 

 tigations. 



These tables supply a desideratum in the English language, and will 

 doubtless be highly prized by all engaged in physical research. It is 



