February 3, 1905.] 



SCIENCE. 



175 



perature. These cold, wet periods are 

 characterized by a raore rapid atmospheric 

 circulation and a lower average latitude 

 of storm tracks. Investigation of grain 

 prices in England from about 1265 shows 

 variations in a cycle of 36 years, high 

 prices corresponding with cold, wet periods. 



Wolfer's epochs of maximum and mini- 

 mum sunspots from 1610 show that the so- 

 called 11-year period is a variable interval, 

 ranging from 8 to 16 years. These vary- 

 ing intervals have a periodicity of about 

 36 years and it is found that periods dur- 

 ing which the sunspot interval is at a mini- 

 mum are characterized by maximum sun- 

 spot and auroral manifestations. This 36- 

 year cycle in solar phenomena has been 

 traced back to about 1000 A. D. by util- 

 izing the 'probable maxima' of Fritz. The 

 sun may, therefore, be regarded as a varia- 

 ble star, whose mean period of variation 

 undergoes a cyclical variation in length. 



Comparing the solar and meteorological 

 epochs in the 36-year cycle from 1050 to 

 1900, the epochs of maximum solar ac- 

 tivity, as evidenced by a decreased length 

 of the sunspot period, are shown to precede 

 the epochs of low terrestrial temperatures 

 by from seven to ten years. 



A long-period variation of about 300 

 years is shown by variations in solar spot- 

 tedness, in the ratio a : h, and in the length 

 of the 36-year cycle ; the ratio a : h and the 

 length of the cycle decreasing with increas- 

 ing solar activity. This cycle of 300 years 

 is traced in solar variations during the past 

 thousand years and is also apparent in 

 meteorological variations, as shown by the 

 records of the time of vintage of Dijon, 

 France, since 1400. 



Tables showing solar and meteorological 

 epochs were exhibited. 



Temperature Corrections of the Zenith 

 Telescope Micrometer, Flower Astronom- 

 ical Observatory: Professor C. L. Doo- 

 LiTTLE, University of Pennsylvania. 



Results from Observations of the Sun, 

 Moon and Planets for 26 Years: Pro- 

 fessor J. R. Eastman, Andover, N. H. 

 The only continuous and complete set of 

 observations of the sun, moon and planets, 

 in this country, was made at the Naval Ob- 

 servatory from January, 1866, to June 30, 

 1891. This work was continuous with the 

 observations of the standard and miscel- 

 laneous stars, and most of the results were 

 found to be affected by the same errors that 

 modified the results for the stars, and also 

 by errors peculiar to observations of bodies 

 presenting in the telescope large disks, like 

 those of the sun and the moon, smaller ones 

 like those of major and minor planets. The 

 errors pertaining to the stars were dis- 

 cussed in the introduction to the 'Second 

 Washington Catalogue of Stars'; and more 

 in detail in a paper read at the last Boston 

 meeting of this association. 



The second class of errors mentioned 

 above was considered and it was shown 

 that there is a high probability of the pres- 

 ence of peculiar errors in solar, lunar and 

 planetary observations with all large in- 

 struments where measures are made of 

 both coordinates. 



Determination of the Solar Rotation Period 

 from Flocculi Positions : Mr. Philip Fox, 

 Yerkes Observatory, Williams Bay, Wis. 

 This determination is based upon meas- 

 urements of flocculi positions on spectro- 

 heliograms obtained at the Kenwood 

 Observatory during the spot-maximum of 

 1892- '93- '94. The method of measure- 

 ment devised by Mr. Hale, that of project- 

 ing the plate upon a globe whose surface is 

 ruled in degrees of longitude and latitude, 

 proved to be accurate and rapid. Motions 

 for proper orientation of the image upon 

 the globe were provided. The results ob- 

 tained from measurements of about 1,000 

 points have been grouped in zones 5 wide 

 and are exhibited in the following table: 



