3o8 POPULAR SCIENCE REVIEW. 
ELECTRICAL SIGNALLING AND THE SIPHON 
RECORDER. 
By J. MUNRO, Assistant to Sir W. Thomson. 
P ERHAPS most, if not all, animals have, in some degree or 
other, the power of communicating intelligence. For 
this purpose birds and mammals chiefly exercise the vocal 
organs, acd many of these give manifest signs of a considerable 
acquaintance with the 64 art of talk.” The parrot and prairie- 
dog, indeed, are reputed gossips ; and, as all the senses can be 
made channels for intelligence to pass along, we shall perhaps 
find the voiceless fishes and serpents to be, like many other 
people, more sociably inclined when we know them better. 
Man, quickly cognisant of his own physical attributes, and 
finding his needs far exceeding their utmost avail, employs the 
subordinate forces of nature, and extends himself. Ordinarily 
one man cannot speak intelligibly to another beyond a distance 
of 200 yards, and the movements of a man 850 yards away are 
barely distinguishable. So no wonder we find that from very 
early ages man availed himself of penetrating sounds and con- 
spicuous exhibitions of motion, form, and colour for the pur- 
poses of telegraphy. 
For obvious reasons night signalling by fires and torches was, 
in ea^rly times, much commoner than day signalling ; and we 
are told in the classics that Clytemnestra watched the beacon 
fires light up the hills across the iEgean Sea, announcing the 
return of the heroes from 66 windy Troy.” But even in these 
present days of the brilliant electric light, when a sunbeam can 
be flashed nearly 100 miles from a mirror, and the commercial 
marine code of flags provides for 78,000 distinct signals, the 
wonders of the electric telegraph far transcend all other modes 
of signalling ; and, although apathetically regarded by Brown, 
Jones, and Robinson, Would not fail to excite the wildest sur- 
prise, even superstitious awe, in the breasts of those more im- 
pressionable ancients who passed away before the dawn of this 
the zinc and copper age- Now neither eye nor ear is hampered 
