The November Shooting Stars. 195 



greatest at about a quarter past six, when the meridian of 

 London is a diameter of the disk. The effects due to this 

 cause of variation ought to be considered in estimating;; the 

 actual changes in the richness of the shooting star-stream as 

 the earth traverses different strata. For instance, the increase 

 which actually occurred after midnight, last November, was 

 partly due to this cause, while the diminution which took place 

 subsequently to Ih. 30m. or lh. 45m., was partly checked by 

 this cause. 



Let us stay for a moment to compare with the effects just 

 considered, those occurring in other latitudes. It is clear 

 from Figs. 1 and 2, that countries in northern latitudes are 

 more favourably situated than countries in southern latitudes, 

 as respects their chance of seeing the November star-shower. 

 Thus, if we consider the short part of the arc traversed by Cape 

 Town, which lies within the darkened part of the disk, it is clear 

 that the a priori probability that observers there will see the phe- 

 nomenon is small. The hour at which Cape Town reaches the 

 diametral meridian being about 6h. 15m., Cape time, it is 

 clear that the moment at which Cape Town enters on the part 

 of the disk visible from the radiant point, is about 2h. 15m. 

 The oval round Cape Town begins to enter this part of the 

 disk rather more than one hour earlier. Thus, unless the pheno- 

 menon occurs between about one o'clock and day-break (it 

 will be seen that Cape Town enters the enlightened half disk, 

 •or, in other words, the sun rises there soon after five), it will 

 not be seen at all at Cape Town ; and that it should be well 

 seen, it is necessary that the epoch of maximum richness 

 should occur between lh. 30m. and 3h. 30m. Cape time. It 

 happened last November, that the shower reached its maxi- 

 mum at 2h. a.m., Cape time, and was, therefore, well seen 

 there.* 



In tropical regions north of the equator, which enter on 

 the hemisphere turned towards the radiant during the con- 

 tinuance of the shower, the display is likely to be grander 

 than elsewhere, since the circular space around any point in 

 such regions would be seen as an oval of much less eccentri- 

 city than that round places in high latitudes, during a part at 



* For the same reason that meteors are more commonly seen in northern lati- 

 tudes from July to December, they are more commonly seen in southern latitudes 

 from January to June. An examination of Figs. 1 and 2 will illustrate the cause 

 of this peculiarity, viz. : — the presentation of the northern and southern poles 

 respectively towards the direction of the earth's motion. It is worthy of notice 

 that Mr. Maclear records the observation of several meteors last November, before 

 the hour at which Cape Town (or the space included within the oval in Fig. 2) 

 entered on the hemisphere turned towards the radiant ; or, in other words, before 

 the radiant rose above the horizon : but none of these belong to the November 

 system, as is evidenced by the direction of their motion. 



