I'liKSlUKNT S AUDUK^S 



Whether some of the finer parts of the ejected dust were 

 carried up so far through the air as to produce the wonderful 

 effects of aerial glow which, during some months, made the 

 mornings and evenings all over the globe so marvellously 

 beautiful, and which are said to liavc seriously affected the 

 quantity of gas consumed in tliis country, may perhaps still ])c 

 held to be not proved. Many considerations go to show the 

 possibility, indeed almost the probability, of such a belief, and 

 an objection which appears on the face of it to be almost 

 msuperable, viz., the difficulty of imagining tlic possibility of 

 fine dust being driven for such a distance through the densest 

 part of the atmosphere, has been proved by some previous cases 

 to have less force than we might be disposed to allow to it. For 

 instances are recorded in which the fine ashes from a volcano 

 have been carried more than one thousand miles in the direction 

 /roni which the trade -winds were blowing, showing that they had 

 been forced through the lower stratum of air into that of the 

 upper currents, the return Trades. 



The recently reported volcanic phenomena in Alaska make 

 it probable that if the particles producing the aerial glow were 

 really due to terrestrial sources we may owe a portion at any 

 rate of the atmospheric dust to the eruptions observed there. 



Another effect of this great explosion was the enormous 

 sea-wave which it raised. This was reckoned at nearly 100 ft. 

 high, and affected the tide gauges at Panama, having traversed 

 nearly half the circumference of the earth by a somewhat 

 circuitous route. Unfortunately details appear deficient, or 

 there might have been some valuable hints gleaned as to the 

 average depth of the sea in various directions, similar to those 

 deduced for the Pacific Ocean from observations of the rate of 

 passage of the great wave raised by the Peruvian earthquake of 

 August 13tli, 1868, Avliich traversed the space from Arica to the 

 Sandwich Islands at the rate of 417 miles per hour, from 

 Avhich the average depth along that line was calculated to be 

 2,500 fathoms. The effect on the atmosphere, also, of the 

 disturbance is said to have been observed at very distant stations, 



