Mr. Swinburne, in replying, said he had not made a perfect condenser yet, for, although he had some which did not heat much, they made a great noise.  He did not see how the rise of pressure observed by Mr. Ferranti and Mr. Kapp could be due to resonance.  Mr. Kapp’s experiment was not conclusive, for the length of spark is not an accurate measure of electromotive force.  As regards Mr. Mordey’s observation, he thought the action explicable on the theory of the leading condenser current acting on the field magnets.  The same explanation is also applicable to the Deptford case, for when the dynamo is direct on, the condenser current is about 10 amperes, and this exerts only a small influence on the strongly magnetized magnets.  When transformers are used, the field magnets are weak, while the condenser current rises to 40 amperes.  Mr. Blakesley’s method of determining losses was, he said, inapplicable except where the currents were sine functions of the time; and consequently could not be used to determine loss due to hysteresis in iron, or in a transparent dielectric.—­Nature.

* * * * *

THE TELEGRAPHIC COMMUNICATION BETWEEN GREAT BRITAIN, EUROPE, AMERICA, AND THE EAST.

By GEORGE WALTER NIVEN.

There are at present twenty-six submarine cable companies, the combined capital of which is about forty million pounds sterling.  Their revenue, including subsidies, amounts to 3,204,060L.; and their reserves and sinking funds to 3,610,000L.; and their dividends are from one to 143/4 per cent.  The receipts from the Atlantic cables alone amount to about 800,000L. annually.

The number of cables laid down throughout the world is 1,045, of which 798 belong to governments and 247 to private companies.  The total length of those cables is 120,070 nautical miles, of which 107,546 are owned by private telegraph companies, nearly all British; the remainder, or 12,524 miles, are owned by governments.

[Illustration:  MAP SHOWING CABLES FROM GREAT BRITAIN TO AMERICA AND THE CONTINENT.]

The largest telegraphic organization in the world is that of the Eastern Telegraphic Company, with seventy cables, of a total length of 21,859 nautical miles.  The second largest is the Eastern Extension, Australasia and China Telegraph Company, with twenty-two cables, of a total length of 12,958 nautical miles.  The Eastern Company work all the cables on the way to Bombay, and the Eastern Extension Company from Madras eastward.  The cables landing in Japan, however, are owned by a Danish company, the Great Northern.  The English station of the Eastern Company is at Porthcurno, Cornwall, and through it pass most of the messages for Spain, Portugal, Egypt, India, China, Japan, and Australia.

The third largest cable company is the Anglo-American Telegraph Company, with thirteen cables, of a total length of 10,196 miles.