Meteorology 667 



tion, whose services cannot be overestimated, since they not 

 only furnished information relating to meteorology, but they 

 were always ready to supply information and assistance in 

 other directions. To that body of men the National Museum 

 owes a very large part of the extensive and complete series 

 of illustrations of North American natural history that gives 

 to it so great a prominence, this being the result of succes- 

 sive applications for aid from particular classes. Thus, when- 

 ever the attention of the Institution was directed to the fact 

 that some particular branch of natural history required its 

 fostering care, circulars were prepared and issued to the 

 meteorological correspondents, invoking cooperation, and 

 asking them to collect objects of the kind that might be found 

 in their neighborhood, so that, not only all North American 

 species might be gathered, but accurate determinations made 

 of their geographical distribution. Very extensive responses 

 usually followed these appeals, and in many cases sufficient 

 material was secured to place the subject on a permanent and 

 satisfactory basis. The works of the Institution on many 

 orders of insects and on fresh-water and land shells, reptiles, 

 birds, mammals, etc., were all based more or less entirely on 

 collections and information obtained by the Smithsonian ob- 

 servers. 



" As a result, therefore, of over twenty-five years' observa- 

 tions by such men, the mass of meteorological information 

 obtained became very great, and even though a certain per 

 cent, of the observations could not lay claim to that minute 

 accuracy which is generally required, yet it was found that, 

 for many purposes, such as the general indications of varia- 

 tions in temperature, barometrical pressure, rainfall, etc., in 

 the collation of all observations the errors disappeared, and 

 an average was secured which did not differ essentially from 

 what would have been derived from more accurate obser- 

 vations." * 



The Smithsonian Institution is also entitled to credit for 

 gathering the following material relating to the climate of the 



1 " Smithsonian Report," 1878, pages 25, 26. 



