Xo. 52812. 



Altitudinal Barometers, Barographs, Boyle's Law. 



377 



52 808. 1 : 3. 



sol 



52809. 1:7. 



52812. 1:7. 



52811. 1:10. 



52.806. Metal Barometer with Bourdon Tube, Figure, 130 mm diameter, very sensitive 



52.807. - - idem, with scale 200 mm in diameter 



52.808. Aneroid Barograph, Figure, with 8 boxes, 8-day mechanism 



52.809. --idem, Figure, highly sensitive, with large deflection combined with high 

 accuracy 



This instrument, is employed for investigating sudden fluctuations of pressure attendant on the 

 occurrence of storms, cyclones and meteorological phenomena generally. As an amplitude of 10 or 

 25 mm is recorded for 1 mm pressure-difference, an estimation to 0.01 mm can be made. 



52.810. Recording Mercurial Barometer, Figure, a very accurately indicating instrument 



Deflection on the drum amounting to 3 mm for every 1 mm of the mercury column. 



52.811. Boyle's Law Apparatus, Figure, after Feilitzsch, as altered by Weinhold (W. D., 

 Fig. 139 [127]), 2.2 m high 



52.812. --idem, with the addition of a Glass Vessel, Figure (W. D., Fig. 344 [324]), 

 to enable the apparatus to be used for determining the coefficient of expansion of 

 gases at constant volume or as an Air Thermometer 



CI. 880,881, 

 886, 885. 



S. d. 

 1.10.0 



1 2. 0. 

 6. 0. 



17.10.0 



15. 0.0 



2.14.0 



3. 6.0 



