450 SCIENCE PROGRESS 



of meteors have been calculated from multiple observations 

 of the some objects. 



The data which have been gleaned will be of inestimable 

 value to future inquirers. The materials we have been storing 

 up will form the basis for the building of important theories 

 when the time is ripe for the consummation. For it must be 

 admitted that our knowledge is still far from perfect, and that 

 certain observed features of meteoric showers have never 

 received adequate explanation. 



Though no very brilliant achievement can be said to have 

 marked our progress in this field since the identity of cometary 

 and meteoric orbits was fully demonstrated, yet many important 

 items can be referred to as forming enduring links in the 

 chain of our advance. 



A generation and more ago the radiant point of the great 

 display of August was supposed to be of normal character. 

 Its position near j] Persei had been pretty accurately fixed by 

 Greg and Herschel, Schmidt, Tupman and others. The shower 

 was supposed to last some days, possibly weeks ; and it was 

 uncertain whether the radiant was elongated, diffuse, mobile, 

 or fixed. Twining in America had thought it moved to east 

 from some observations he secured ; but his materials were 

 insufficient to prove anything. Greg considered the radiant 

 an elliptical area, with major axis from north to south. Others 

 regarded the centre as constant, but the area of radiation an 

 extensive one. 



The matter was set at rest in 1877 and 1878 by observations 

 at Bristol. It was found that the radiant moved to the E.N.E. 

 at the diurnal rate of i°, and that the display certainly lasted 

 a month if not more. These observations were shown by 

 elaborate mathematical investigations by Kleiber (Monthly 

 Notices R. A. S. B. 1. 341) to be remarkably in accord with 

 theoretical deductions. The observed radiants and those 

 computed agreed within 2 ; and this must be held to be very 

 satisfactory, when we remember that records of meteor flights 

 necessarily depend upon hurried eye estimates of position. 

 Moreover, the radiant often appears diffuse or scattered owing 

 to deflected or perturbed meteors, and is not a point upon 

 which the tracks sharply converge ; so that its precise location 

 is by no means easily fixed. 



The radiant of the April meteors has shown similar indica- 



