1874.] Curved Appearance of Comets’ Tails. 515 
sphere of the comet’s “attraction, and consequently cease 
to follow the direction of the nucleus.” 
This explanation needs no further comment; it is but a 
specimen of a class of so-called science which is in the 
present day very extensively followed. Just as a savage 
who has once seen an ele¢tric telegraph will hope to explain 
everything from the effervescence of champagne to the moving 
of a locomotive by attributing theseZeffects to electricity, so 
his mental type in England endeavour to explain each 
astronomical effeét by attributing it to the laws of 
gravitation, to ‘“‘impulsion,” ‘‘ attraction,” &c., causes 
which, as in the present case, have often nothing whatever 
to do with the question under consideration. 
Other important problems connected with astronomy are 
dependent on these same geometrical laws, and will be 
treated of at another opportunity. 
