556 SCIENTIFIC RECORD FOR 1883. 



These differences are apparently largely due to mechanical impurities 

 in the atmosphere, such as are washed away by every rain or snow-fall, 

 and their importance can be seen from the fact that from observations 

 on the Brocken it is proved that only one-third of the sunrises and sun- 

 sets can be clearly seen and these are pretty uniformly distributed 

 through the year. 



The ordinary observation of amount of cloudiness gives little or no 

 idea of this obscuration of the solar rays ; thus during the interval cov- 

 ered by the above observations the average cloudiness for all the above 

 high stations was almost exactly the same as for the low station G les- 

 sen. 



The thermal constant of vegetation must, of course, begin at some 

 epoch uniform for all plants. Hoffmann confines himself to plants with 

 closed winter buds and takes the time of first swelling of the buds as 

 the date for which to begin the summation of temperature. 



In order to ascertain this movement he paints in black a broad line 

 on one side of the trees and daily observes with a lens until he discerns 

 white lines breaking open in the blackened portion ; he finds that the 

 dates can be thus ascertained to within one day when the temperature 

 rapidly increases, but to only within a week when the temperature in- 

 creases slowly and regularly. (Z. 0. G. M., xvn, p. 30.) 



METEOROLOGICAL BIBLIOGRAPHY, 1882 AND 1883. 



Abbe, Cleveland. Account of progress in meteorology and allied 

 subjects, 1879-1881. W., 1883. 8vo, pp. 101. (From Smithsonian 

 report, 1881.) 



Adelaide Observatory. Meteorological observations, under direction of 

 Oh. Todd, 1880. Adelaide, 1882. 4to, pp. xxv + 305, ch. 36. 



Algiers. Service me^orologique. Bulletin inel^orologique (daily, with 

 chart), 1882-1883. 1. 8vo. 



Resume climatologique (monthly), 1882, January-September. 



fol. sheets. 



Anderson, B. The lightning rod. On the necessity for a regular in- 

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Associazione meteorologies* italiana. 1 assemble* generale nella cittadi 

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Bolletino decadico, pubblicato per cura dell' Osservatorio cen- 



trale del collegio Carlo Alberto in Moncalieri (monthly), xi, xn, 

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Bolletino mensuale. Serie 2, n, in, 1882-1883. Torino, 18S2- 



1883. 2 vols. 1. 8vo. 

 Attlmayr, T. Handbuch der Oceanographie und maritimen Meteoro- 



logie. Wien, 1883. 2 vols. 8vo. 

 Atjgustin, F. Ueber den taglichen Gang des Regenfalles. Prag, 



1882. 8vo, pp. 30, pi. 2. (From Sitzb. k. bokin. Ges. Wissensch.) 



