METEOROLOGY. 31 



of intensity and mijiht mean something really definite instead of mere guesswork. 

 For tills piuposo a pliotographic scale was constructed, consisting of a series of 

 lines regularly increasing in intensity from a line barely visible to others as strong 

 as were desired. 



" A large, narrow slit was used, Avith a gaslight behind it and a plate of ground 

 glass between theiu to jjroduce a more even light. A series of images of the slit 

 •was then made upon a i)hotographic jdate held in a camera, the Ions of which had 

 been covered with a piece of wire gauze line enough to produce a shading to the 

 edge of the lines and a somewhat diffuse appearance of the lines theiiiselves, but 

 not sufticieutly line to ])roduce any definite side lines due to diffraction fringes. 



'' In the scale thus constructed the exposures were so timed as to be in geometrical 

 ratio, the object being to form a scale of lines whose intensity should vary, as the 

 geometrical series 1, 2, 4, 8, 10, etc. These lines formed the principal divisions, 

 "while, to facilitate measurements, an intermediate line was added by making the 

 ratio of the series 1.114 or v'2." 



The author concludes from the results of his observations that this 

 method may be of great value in studying- the distribution of water 

 vapor in the atmosphere, but that it is of little use for regular observa- 

 tions upon which to base weather forecasts. 



The diurnal lunar "waves and the secular variations of the 

 barometer, P. frAiiniciON-LAGRANGE [Compt. Rend., l:J2 {1S96), iVo. 

 lo^ m). S46-S49). — The author coucludes from his investigations that 

 the action of the moon on the atmosphere is very marked, amounting 

 on the 10th parallel to 1.2 mm. of mercury. This action may be attrib- 

 uted to the law of universal attraction, and appears to manifest itself 

 not only in daily and semidaily oscillations, as in the case of tides, but 

 is also exerted through monthly, annual, and secular periods. 



North Carolina weather during the year 1895, H. B. Battle, 

 C. F. VON Herrmann, and E. Nunn {North Carolina State Weather 

 Service Bpt. 1895, pp. I-L, 1-204, maps 20). — This report includes lists 

 of publications of the State Weather Service during 1895, lists of 

 meteorological stations and observers and crop correspondents, notes on 

 the distribution of forecasts in the State, and a meteorological summary 

 for the year as comi)ared with i)revious years (1882-'94), with general 

 remarks on the climate of Korth Carolina and on the weather and cro}) 

 conditions during 1895, and charts of normal annual temperature and 

 precipitation for the State. Meteorological bulletins issued during the 

 year are published as an appendix. 



The annual summary is as follows : 



Temperature (degrees F.). — Mean, 57.4; normal, 59; departure, — 1.0; maximum, 

 104, .Tnne 2 and 3, and September 22 and 23; mean maximum, 07.6; iniuimum, — 18, 

 January 13; mean minimum, 47.4; mean HHmthly range, 51; mean daily range, 20.2; 

 absolute range, 122. Pressure (inches). — Mean, 30.09; normal, 30.08; departure, 

 +0.01; maximum, 30.77, December 17; minimum, 29.28, Fel)ruary 7; absolute range, 

 1.49. Relative humklity. — Normal (per cent), 74.6. rrecipitntUm (inches). — Average, 

 50.23; normal, 53.29; departure, —3.06; greatest monthly, 14.84; least monthly, 

 0.05. Wind. — Prevailing direction, SW. ; average direction for many years, SW. ; 

 maximum velocity (miles jier hour), 66. Weather. — Number of clear days, 160; 

 number of cloudy days, 98; number of rainy days, 108; number of partly cloudy 

 days, 107. 



