136 Dr. GreGory on the 
(See Savart’s interesting papers on the communication of .so- 
norous vibration. ) 
6th, Whether sound would not employ a longer interval in 
passing over a given space, as a mile, vertically upwards, than 
in a horizontal direction? and, if so, would the formula which 
should express the relation of the intervals include more than 
thermometric and barometric coefficients ? . 
7th, Whether, or not, the principle of the parallelogram of forces 
may be employed in estimating the effect of wind upon sound, 
when their respective velocities do not aid, or oppose each other in 
the same line, or nearly so? 
8th, Whether those eudiometric qualities, generally, (whether 
hitherto detected or not) which affect the elasticity of the air, will 
not proportionally affect the velocity of sound? and if so, how are 
the modifications to be appreciated ? 
To the experimental solution of some of these enquiries I hope 
to devote myself at no very remote period: but others of them, it 
is evident, can only be satisfactorily answered, if ever, by means of 
a cautious classification of skilful experiments made by various 
philosophers in different parts of the globe. 
OLINTHUS GREGORY. 
Royal Military Academy, Woolwich, 
October 25, 1823. 
Postscript. Since the above paper was drawn up, a friend has 
favoured me with the perusal of Mr. Goldingham’s account of his 
experiments in reference to the velocity of sound, made at Madras. 
From this very interesting Dissertation I shall venture to transcribe 
the following Table of the mean motion of sound for each month 
of the year, at Madras. 
