264 BULLETIN OF THE NATURAL HISTORY SOCIETY. 



The anemometer is of the Robinson pattern, and with the wind 

 vane records electrically the direction and velocity of the wind upon 

 the register. The register has three essential parts, — the cylinder, the 

 clock and the electro magnets. A specially ruled sheet is placed upon 

 the cylinder and revolved by means of clock work ; the direction of 

 the wind is printed upon the sheet every five minutes, and a mark is 

 made at right angles to the direction of the revolution of the cylinder 

 for each mile of wind, and the number of marks within a given space 

 shows the rate per hour at which the wind is blowing. The sheet 

 placed on the cylinder holds the record for twenty-four hours. 



The rain gauge has a circular receiving surface equal to ten square 

 inches. No snow gauge is used, but it is assumed that ten inches of 

 snow equals one inch of rain. 



The astronomical equipment is intended specially for the determina- 

 tion of correct time. The transit room is situated on the western 

 side of the building, and the transit telescope is mounted on a sub- 

 stantial brick pier, capped with stone. It is of modern construction 

 by Troughton & Simms, London, has an object glass of two and a half 

 inches diameter, two setting circles attached to the tube, micrometer 

 eye pieces and electric illumination. Observations of stars on the 

 meridian are made with this instrument for the correction of clock 

 errors and rates. 



The standard sidereal clock by Victor Kullberg, London, was 

 received at the Observatory in September, 1899. It has a zinc and 

 steel compensated pendulum, similar to the standard sidereal clock of 

 the Royal Observatory, Greenwich, a central steel rod being surrounded 

 to about the middle of its length by a tube of zinc, and then incased 

 by an outer tube of steel. The latter carries the lead bob, which is 

 cylindrical in shape (weighing forty pounds) and suspended at the 

 middle of its height, thus eliminating the temperature changes in the 

 bob itself. This clock is of the best construction, and is fitted with 

 break circuit attachment for operating chronograph. The movement 

 and pendulum are mounted on a solid iron bracket, which is firmly 

 bolted to heavy masonry ; the iron base and bracket also carries the 

 case of solid teak. To prevent sudden changes of temperature from 

 affecting the clock, it is enclosed in a closet which is thickly padded 

 with felt. 



