88 THE BUTTERFLIES OF NEW ENGLAND. 



to the data o-iven in Schott's Smithsonian Tables, and in the latest Annual 

 Report of the Chief Signal Officer, supplemented in a few cases by obser- 

 vations reported to the New England Metereological Society ; but they can 

 be regarded only as approximations, especially in the north, for they 

 depend in most cases on series of observations of insufficient duration and 

 of different lengths and dates. The temperatures indicated are actual 

 means, no reduction to sea-level having been applied. There are no 

 records for northern Maine. The mean annual for the rest of New 

 England may be concisely descril^ed as ranging from 40° in the north to 

 50° on the southern coast : the winter mean varies from 15° in the north 

 to 30° in the south : the summer mean varies from 60° to 70°. On Mount 

 Washington, the annual, winter and summer means are 26°, 7° and 46°. 

 The annual precipitation at low-level stations, as given in the sources 

 above named, varies from thirty-five inches in the northwest, to fifty 

 inches in the south and along the coast, except in southwestern Maine, 

 where it is somewhat less ; but these numbers give an inadequate measure 

 for all New England, as Mount Washington has an annual precipitation 

 of eighty-five inches for thirteen years record ; from which it may be inferred 

 that much of the White and Green Mountain areas have totals at least 

 above sixty inches. The distribution of the precipitation through the year 

 is fairly equable, with a slight maximum in late summer and a minimum 

 in early Avinter, these variations being rather more marked in the west than 

 near the coast ; the irregular variations from year to year are rather strong. 

 The winter snow is heavy in the northern interior, where sleighing is 

 hardly interrupted for three months ; in the south and near the coast, occa- 

 sional mild rains in midwinter may melt the snow to the ground. Frost 

 is occasionally reported even during the summer season in the north. Hail 

 is not common or severe enough to be considered as a climatic factor. 



BIBLIOGRAPHY. 



TbemakTiul for the foregoing chapters is derived in part from the following pnhlications. 



The geological surveys of the several New England States, especially of New Hampshire 



and Vermont. 

 Appalachia. Many articles on the mountains of New England are to be found here. 

 L. Agassiz. Geological Sketches. Boston, ISOG. 

 J. D. Dana. On southern New England during the melting of the great glacier. Amer. Journ. 



Sc. X, 187"), 1G8 ; and other papers. 



B. K. Emerson. A chapter on the geology of Hampshire County, Mass., in the Hampshire 



County Gazetteer, 1887. 

 H. Gannett. Dictionary of altitudes in the United States. Bull. No. 5, U. S. Geol. Survey, lss4. 



C. E. Hamlin. Oljscrvations upon the physical geography and geology of Mt. Ktaadin and 



the adjacent district. Bull. Museum Comp. Zool. vii, 1881, 189-223. 

 L. L. lluhhard. The woods and lakes of Maine. Boston, 1884. 



F. J. II. Merrill. On the geology of Long Island. Ann. N. Y. Acad. Sc. iii, 1885, 3H-;](J4. 

 E.C.Pickering. Accurate mountain heights; and Heights of the White Mountains. Api)a- 



lachia, iv, 1880, 2ir.-21!i, and 305-322. 



