laid without obstruction; there are intermediate stations at Tripoli and 
Bengazi. The completion of this line will enable us to hold communi- 
cation with India in 13 days. 
At the same time a new cable is being laid between France and Al 
tia; this new cable starts from Port-Vendres ; the first section is already 
laid, reaching to Mahon. wilt j 
fw system of cables.—Sub-marine communications are easily estab- 
lished where they are to operate only for distances comparatively small. 
The length of the cable between Malta and Alexandria is 1400 miles, 
Great distances are attended by difficulties which have been so frequently 
Mentioned that it is not necessary to repeat them here; we will merely 
say that the cables in use are much too heavy, and hence the iron wire 
twisted upon the outside as a protection by stretching (with no fault of 
the manutacturers) ruptures the conducting wire. Pag 
The new cables are much lighter; the spiral armature of iron is there 
replaced by a simple envelope of textile material, so that it resembles 
very much an ordinary ship cable. The weight does not much exceed 
that of the volume of water which it displaces, so that descending slowly 
c 
it does not acquire that prodigious tension which ause fractures of the 
Yacuum, so that the interior may be as much as possible freed from air. 
hysiological effects of the Electric Telegraph.—lt appears that con- 
stant Watching of the needles of electric ial-plates begins at length to 
Produce an unpleasant effect upon the eyes of some of the operators. 
After laborious service, and especially after service at night, the retina is 
frequently So affected that for a considerable time all objects appear double 
and shrouded in a haze. ‘This affection is developed only at those stations 
Am fir 
= letters with a velocity which permits the transmission of twenty 
or thirty words per minute: ‘ : : 
duces everything autographically, writing, linear drawings, portraits, land- 
¢. we., with a velocity of eight to * words of ordinary writing 
°r 60 words written with the characters of Morse. és, 
Army Lelegraph.—In July last the French Minister ag eed _— 
‘ome experiments to be made in the Champ de Mars vag e Pecan 
vi et us see in what these experiments consisted : ia 
ber of mounted artillerists were followed by a vehicle properly a — 
which were placed lances designed to serve as telegrap sey * om 
eetric conducting wire. At a given signal they quickly extend 
f the cae’ the line; this signal was given as soon as = sag Hgts 
® the conduetor was fixed to th be 4 
distanee of thirty metres a horseman dismounted, took a lance given him 
- by an artillerist in the carriage, and set up the lance in the earth, causing 
