150 ANNUAL OF SCIENTIFIC DISCOVERY. 



deficiency. In its stowage in the vessel for transportation, the greatest care 

 has been exercised owing to the enormous weight, and the circumstance 

 that it is all in one piece. Seventy-one miles of it have been put in the 

 lower hold, forty-two miles on the orlop deck, thirty miles in 'tween decks, 

 seven miles in the after hold, and the twelve spare miles of what is called 

 small cable, although it weighs five tons to the mile, is also on 'tween decks, 

 and every one of these portions has to be shored at very short intervals, to 

 prevent the movement of the cable. 



In laying down the last portion of the cable, that between Spezzia and 

 Corsica, it took five days, including the stoppage that had to take place in 

 cutting the cable, and going round to lay the short lengths between Corsica 

 and Sardinia. It is expected that the present cable will be laid down in 

 four days. The Mediterranean Telegraph Company anticipate that in two 

 years and a half they will have a direct communication with Bombay, and 

 thence, by telegraphs already at work in the presidencies, to Calcutta ; and 

 they consider this line they are just about to complete as only the preliminary 

 step to this result. Their proposed line, joining the one at present open to 

 Cagliari at Cape Spartivento, will first be taken to Malta, and thence direct 

 under the Mediterranean to Alexandria. This will be an immense distance : 

 984 miles of submarine cable without a station ; from Alexandria to Suez, 

 by land, 248 miles ; another submarine cable under the Eed Sea to Aden, 

 with two stations, Cosiri and Licldah, 1,552 miles, and from Aden to Bombay, 

 with stations at the Kooria Moorta Islands and Ras-al-had, 1.900 miles. 

 When this undertaking is completed the communication with Calcutta, which 

 now takes on average thirty-six days, will be reduced to a few minutes. 

 Professor Faraday, about two years ago, called the attention of telegraph 

 companies to the fact that there was great difficulty in sending any commu- 

 nication through a greater length of wire than 300 miles ; but since that time 

 Mr. Brett, the Superintendent, has been experimenting, with a view to over- 

 come this difficulty, and has perfectly succeeded in doing so. By connecting 

 each individual wire in this coil of six, and also those belonging to another 

 cable intended for an American company, he was enabled to experiment on 

 a length of 1,250 miles with perfect success, and he has prepared a new in- 

 strument for use with wires of great length. 



ELECTRIC TIDE-GUAGES AND REGISTERS. 



Throughout the long extent of the American sea-board there are many 

 harbors, much frequented by coasting and other vessels, w^here the entrances 

 are blocked by sand-bars or reefs, over which, at certain stages of the tides, 

 there is not a sufficient depth of water to permit safe navigation. The same 

 may be said of various shoals. It is often a matter of difficulty for a mariner, 

 in approaching such places, to determine whether or not the depth is suffi- 

 cient for his vessel : through a want of correct information he is often de- 

 layed from going into port, and is driven off by a storm ; or, what is more 

 frequent, his ship strikes bottom, and becomes a wreck. An invention by 

 Alex. Boyd of New York, is intended to guard against these difficulties. 



