At Perak—­770 miles off—­the sounds were thought to be distant salvos of artillery, and Commander Hon. F. Vereker, R.N., of H.M.S. Magpie, when 1227 miles distant (in lat. 5 deg. 52’ N. long. 118 deg. 22’ E.), states that the detonations of Krakatoa were distinctly heard by those on board his ship, and by the inhabitants of the coast as far as Banguey Island, on August 27th.  He adds that they resembled distant heavy cannonading.  In a letter from St. Lucia Bay—­1116 miles distant—­it was stated that the eruption was plainly heard all over Borneo.  A government steamer was sent out from the Island of Timor—­1351 miles off—­to ascertain the cause of the disturbance!  In South Australia also, at places 2250 miles away, explosions were heard on the 26th and 27th which “awakened” people, and were thought worthy of being recorded and reported.  From Tavoy, in Burmah—­1478 miles away—­the report came—­“All day on August 27th unusual sounds were heard, resembling the boom of guns.  Thinking there might be a wreck or a ship in distress, the Tavoy Superintendent sent out the police launch, but they ‘could see nothing.’” And so on, far and near, similar records were made, the most distant spot where the sounds were reported to have been heard being Rodriguez, in the Pacific, nearly 3000 miles distant!

One peculiar feature of the records is that some ships in the immediate neighbourhood of Krakatoa did not experience the shock in proportionate severity.  Probably this was owing to their being so near that a great part of the concussion and sound flew over them—­somewhat in the same way that the pieces of a bomb-shell fly over men who, being too near to escape by running, escape by flinging themselves flat on the ground.

Each air-wave which conveyed these sounds, commencing at Krakatoa as a centre, spread out in an ever-increasing circle till it reached a distance of 180 deg. from its origin and encircled the earth at its widest part, after which it continued to advance in a contracting form until it reached the antipodes of the volcano; whence it was reflected or reproduced and travelled back again to Krakatoa.  Here it was turned right-about-face and again despatched on its long journey.  In this way it oscillated backward and forward not fewer than six times before traces of it were lost.  We say “traces,” because these remarkable facts were ascertained, tracked, and corroborated by independent barometric observation in all parts of the earth.

For instance, the passage of the great air-wave from Krakatoa to its antipodes, and from its antipodes back to Krakatoa, was registered six times by the automatic barometer at Greenwich.  The instrument at Kew Observatory confirmed the records of Greenwich, and so did the barometers of other places in the kingdom.  Everywhere in Europe also this fact was corroborated, and in some places even a seventh oscillation was recorded.  The Greenwich record shows that the air-waves took about thirty-six hours to travel from pole to pole, thus proving that they travelled at about the rate of ordinary sound-waves, which, roughly speaking, travel at the rate of between six and seven hundred miles an hour.