1885.] 
T elephonic A udibiliiy. 
265 
° U1 senses are developed in accord with the organisation 
Whln E l ' W f - IVe . at her surface > under h er atmosphere. 
When we ascend in it, and density and incumbent weight 
decrease audibility declines, for the deepest sounds first 
oui C W din ? s J w h en we submit to pressures of more than 
one atmosphere the production of high sounds becomes for 
us mme difficult. Both ways the circulation of our blood, 
and theieby the adtion of our senses, is upset by abnormal 
atmospheric pressure. y 
^ghteen and thirty thousand are round figures: they 
vaiy slightly with the acuteness and expertness of the ear 
0 the operator,” by individual and reciprocal geographical 
position and atmospheric state of connected places, and also 
by astronomical combinations. 
capacit y of a cond uc 5 tor is the quan- 
wMch th,? n 1 y Wlth W , hich ^ is char S ed by the potential 
ilnl , a h l Chai ,' ge produces ln The capacity of an 
its i a t dfus PhenCa COndua ° r ls ec l ual (in numerical value) to 
audib?hfi^ n ^ betWe u r l w 6 18,000 and 3°>ooo, between perfect 
varied tlfp d i lnaudl ? l lt 1 y ’ 1S 24 ’ 000 > th e figure round which 
vanes the radius into the solar distance of the Earth, the 
Sun being the eledtrificator, Sun and Earth standing in 
leCtnc exchange of store of motive current and electro- 
magnetic resistance. To be brief I omit all secondary 
influences and combinations. y 
The Earth is, however, neither a perfect sphere nor a 
inifoim conductor ; capacity differs and oscillates therefore 
locally inside constant amount for the whole Earth. Sound 
entiusted to the insulated wire, both ways abutting into the 
atmo^here, is therefore, by the locally changing influences, 
n the last lesoit all due to or dependent on the contests 
Earth and Sun > half-way between 
commeicml audibility and inaudibility, when the “pro- 
duct of the factors of induction is equal to the quotient of 
the radius into the solar distance of the Earth. 
The (numerical) value of the ohm is identical with that 
0 a velocity of one quadrant of meridian in one second 
(theoretically to about 1-062 seconds), such quadrant being 
in the mean about 10,000,000 metres in length. The 
velocity of sound in air is at i 5 °-22 C., under 760 m.m. 
piessure, 345 metres in a second ; but for the atmosphere in 
its mean, 396 metres ; accelerated and retarded by wind 
^50 metres (see “Journal of Science” — “On Light”— 
, 3 , Nos. 117 and 118) ; 396 metres being also the rotatory 
velocity of the surface of the Earth in its mean. 
VOL. VII. (third series). l - 
