COMET AEJ INFLUENCES. 



measured 1,250000 miles. Its bulk must, therefore, have been 

 thrice that of the sun, and nearly four million times that of the 

 earth I But astounding as this is, the dimensions of the tail were 

 still more so. The length of that vast appendage was an hundred 

 and thirty millions of miles, so that if the head were at the sun, 

 the tail would extend to thirty millions of miles beyond the 

 earth ! 



Supposing this tail to consist of continuous matter, let us see 

 what its quantity must be by measure. Its diameter at the point 

 where it emanated from the head was equal to that of the head, but 

 as its sides were slightly divergent, its diameter increased as the 

 distance from the head increased ; but let us take it as equal only 

 to the diameter of the head. 



The length of the tail having been an hundred and thirty mil- 

 lions of miles, while the diameter of the head was a million and a 

 quarter of miles, it will follow that the length of the tail was 104 



Fig. 3. 



times the diameter of the head. If the sides of the tail, instead of 

 being divergent, were parallel, it would thence follow, by the 

 principles of geometry, that the volume or cubical bulk of the tail 

 must have been an hundred and fifty times greater than that of the 

 head, and since the bulk of the head was four million times that 

 of the earth, that of the tail and head together (without taking into 

 account the effect of the divergence of the tail), must have been 

 nearly six hundred million times the bulk of the earth ! ! 



It must be observed, however, that some appearances observed in 

 the tails of comets have suggested to astronomers the probability 

 70 



