98 Description and System of Working 



mirrors are brought close to the roof, and this again can be 

 removed, so as to expose the instrument entirely to the open 

 air. Round the top part of the just mentioned pillar runs a 

 stage, to which a flight of steps leads from below. 



On the highest portion of the enclosure, distant from all 

 buildings, 



A Meteorological stand {vide G, plate No. 1, also plate No. 

 3) is erected. The little house, if I may call it so, which con- 

 tains the thermometers, is in its principle of construction 

 similar to that of Lawson's, but it received such alterations and 

 additions as to make it respond to the demands of this coun- 

 try, in which the soil attains so high a temperature. To pre- 

 vent all influences of the soil, the stand is raised upon a plat- 

 form five feet above the level of the surrounding ground, the 

 bulbs of the thermometers thus assuming a height of ten feet 

 above the soil, the smallest distance which can be given them to 

 prevent the effects of radiation. To protect the thermometers 

 against sun, rain, and wind, the upper part of the meteor- 

 ological stand is moveable round the flagstaff, which passes 

 through its bottom and roof. A wooden disk, fastened to 

 the bottom of the little house, serves as a limbus, with the 

 help of which, in addition to a small quadrant attached to 

 one of the sides in a perpendicular plane, we are enabled to 

 ascertain, by equal altitudes, the meridian passing through 

 the centre, thus obtaining an excellent means for registering 

 the wind by the vane on the top of the flagstaff. A tin box, 

 of a cylindrical form, containing the ozone paper, is hoisted up 

 to the top of the mast for ozonometric measurements. 



In the close vicinity of this meteorological stand, the Rain- 

 guage {vide H, plate No. 1) is placed, and also the thermo- 

 meter for temperature of soil and radiation; and farther 

 towards the south arrangements have been made for correct- 

 ing the sextants of captains, with regard to eccentricity and 

 the error of division {vide F, plate No. 1). 



The Dwelling-house {vide A, plate No. 1) is chiefly taken up 

 by the offices for computation. The only apartments of parti- 

 cular interest are the front-room, appropriated for barometri- 

 cal observations, the comparison of meteorological instruments 

 belonging to masters of ships, and to the electric telegraph, 

 which brings the Flagstaff Observatory in immediate connec- 

 tion with the Astronomical Observatory at Williamstown. 

 In addition, a little room up stairs should not be forgotten, 

 in which arrangements are made for electrical observations ; 

 the stand for the electrometer is fixed to the wall in a per- 



