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two; South Africa has one, at Cape Town; Toronto, Canada, has one; India has three; Japan has one; Mauritius has one; South America has one, in Argentina; Beirout, in Syria, is in correspondence for one, and so also is Siberia.

In short, there seems to be little doubt that within a few months no fewer than twenty of these seismic stations will be in operation in different parts of the globe, all equipped with the Milne instruments, and all in regular communication with the head, or central, station at Shide. It is taken as certain that a comparison of records from all these earthquake observatories will make it impossible for an important seismic disturbance to occur anywhere, whether on land or under the sea, without its precise location being immediately known, as well as all essential facts regarding it. And when it is borne in mind that at present seventy-five per cent, of the whole number of earthquakes occur in the bed of the ocean, the value of such statistics to cable companies (and what country is not interested in the proper working of ocean cables?) is at once apparent.

Twice, for instance, it has happened in Australia (in 1880 and 1888) that the whole island has been thrown into excitement and alarm, the reserves called out, and other measures taken, because the sudden breaking of cable connections with the outside world has led to the belief that military operations against the country were preparing by some foreign power. A Milne pendulum at Sydney or Adelaide would have made it plain in a moment that the whole trouble was due to a submarine earthquake occurring at such a time and such a place. As it was, Australia had to wait in a fever of suspense (in one case there was a delay of nineteen days) until steamers arriving brought assurances that neither Russia nor any other possibly unfriendly power had begun hostilities by tearing up the cables.

Before explaining the workings of these wonderful seismic instruments which are to do the world such famous service, I will tell how it happened that Professor Milne