﻿6 EQUIPMENT AND WORK OF AN AERO-PHYSICAL OBSERVATOKY. 



Thermodynamics and Chemistry. 



Apparatus might be devised which would give graphically the 

 thermodynamic conditions of the atmosphere. The volume, press- 

 ure, temperature, and density of the air being known, we ought 

 to be able to follow the isotherms and adiabatics through the vary- 

 ing conditions in cj^clone and anti-cyclone at all levels. Thus 

 Hertz (Graphische Methode zur Bestimmung der Adiabatischen 

 Zustandanderungen feuchter Luft, Meteor. Zoits., 1884) has given 

 the adiabatics for the dry, rain, and hail stadia, and it is practi- 

 cable to follow a given air mass through the varying thermody- 

 namic conditions. 



Electrometry. 



Proper apparatus for measurements in atmospheric electricity. 



Mascart-Kelvin electrometers for the determination of the potential 

 of the air. The type of voltmeter known as the multiple quad- 

 rant electrometer, or substantially Lord Kelvin's air ley den, 

 should be installed with an automatic register for continuous 

 records of the electrification of the air. 



Elster and Geitel's apparatus, modified, for records of the air " leak- 

 age " of electrical charge under the influence of ultra-violet light. 



Brontometer, for use in the study of the strains and stresses in air 

 between highly electrified clouds or cloud and earth. The name 

 brontometer is used, but some more appropriate type of instru- 

 ment than the present is desired. It now gives the time of each 

 lightning flash, the duration of thunder, the changes in direction 

 and force of the w^ind, in temperature, humidity, and barometric 

 pressure during a thunder-storm ; but there is wanting, the photo- 

 graphic auxiliaries to delineate the character of each discharge. 

 The true direction in space and the dimensions of the discharge 

 are determinable by such means. The potential fluctuations 

 added to such data will enable us to study the strains and rup- 

 tures in the atmosphere after the thunder-storm as completely as 

 a plate of fractured armor can be studied after a test. 



Physiology and Biology. 



The known properties of atmospheric air are clearly of great impor- 

 tance in all physiological and biological research. In the latter, atmos- 

 pheric environment must be an efl'active factor in the variation of species, 

 and in the former, at the very outset, do we not meet an intimate relation 

 between the irritability of nerve and muscle with atmospheric conditions ? 



