540 BBPOBT— 1881. 



5. On the Velocity Function of a Liquid d%ie to the Motion of Cylinders and! 

 Surfaces of Bevohition. By A. Gr. Geeenhill. 



MONDAY, SEPTEMBER 5. 



The following Reports and Papers were read : — 



PHYSICAL DEPARTMENT. 

 1. Report of the Committee on Meteoric Dust. — See Reports, p. 88. 



2. Report of the Committee on Tidal Observations in the English Channel 

 and the North Sea. — See Reports, p. 160. 



3. Report of the Committee on JJndergroimd Temperature. 

 See Reports, p. 90. 



4. Report of the Committee on the Calculation of Sun-heat Coefficients. 



See Reports, p. 89. 



5. Observations of Atmospheric Electricity at the Kew Observatory during 

 1880. By G.M. Whipple, B.Sc, F.B.A.S.—iiee Reports, p. 443. 



6. On a Universal Sunshine Recorder Stand. By G. M. Whipple, 



B.Sc, F.B.A.S. 



_ A description was given of a new form of card-supporter for the Camphell Sun- 

 shine Recorder, constructed by Mr. L. P. Casella at the suggestion of the author and 

 exhibited to the Section, It consists of a light frame capable of hwlding the slip of 

 cardboard to be burned by the sun in any desired position. It is arranged so 

 as to receive ordinary parallel strips of card at all times of the year, and to allow of 

 the instrument being employed on any part of the earth's surface without detriment 

 to its efficiency. 



The card-holders themselves are movable, so as to permit of the cards being 

 changed indoors or dried if wet, before removal, thereby avoiding tearing or mutila- 

 tion of the record in the operation. The instrument is also furnished with ap- 

 pliances for placing the card correctly in position to receive the sun's image. 



7. On the Calibration of Merciirial Thermometers by BesseVs Method. By 

 Professors T. E. Thorpe, Ph.B., F.R.8., and A. W. Rucker, M.A. 



The authors have recently had occasion to calibrate with great care a number 

 of mercurial thermometers. 



The method adopted was Bessel's, as modified by Arthur von ffittingen (' Ueber 

 die Correction der Thermometer,' A. von Qittingen. Dorpat, 1865.) 



In this there appear to be two weali points, viz., (1) the concentration of the 

 observations on the central part of the scale, (2) the uncertainty as to the best 

 method of uniting the two curves obtained respectively from the ' Ilauptpunkte,' 

 and the other points at which observations are made. These were m part 

 strengthened by introducing the additional measures (used by Arthur von CEttingen 

 in the second approximation only) in the first approximation and by giving to the 

 ' Hauptpunkte ' a higher relative value than is assigned to them by von CEttingen. 

 Under these conditions the method, though very laborious, is capable of giving 

 excellent results. 



