146 Scientific Intelligence. 
Quetelet’s list, in some cases changed to agree with the authority cited. 
approximately corresponding dates of the tropical year. The later dates 
are generally omitted. To express these Sy ied in a sidereal year there is 
given at the same time the corresponding day (and fraction of a day 
1850; that is, hen time when the pase on ude in her orbit, meas- 
ured from a equinox, was the same as on the day of the shower. 
The Sapte. peas is used in the computation 
he number of days to be added fo the actanel date ex- 
pressed in th e Gregorian oe “ the given year of the Christian era, 
n the number of leap years between the given date and A.D, 1850, and 
1 the length in days of the aiictoal § year. Then, evidently, 
(1850 —t) (=2+4-365 (1850—2)-+N. 
To reduce this to a form better suited for computation, observe that 
N is equal to the integral part of $(1851—2), minus 12, plus the cor 
rection between the Gregorian and Julian calendars for the given date. 
Let ¢ be this correction, ¢ be the remainder after dividing 1851—¢ by 4, 
1=3654-256374, and we obtain, by reducin 
x=(185 0= 1) X-00BT44H(¢—1) +12 —« 
The integral part of + 
the value of 12 : 
Itw ill be observed that Oe secular variation in the value of i, the : 
—i 
, Minus the integral part of 
wai apie of longitu e. 
n of the historic date is taken when it is not stated whether 
the te. was in the morning or the evening. This involves an error 
not e n-tenths of a day. It should borne 
that the shower in August (and probably those in other months) must 
be co ed as continuing through more than a single d 
> ita get vol. x, Paris, 1848, to the paper of Chasles in the Comptes 
Rendus, xii, 499, and to Herrick’s, eatalogue of star-showers, this Journal, 
bai 040. 349. oe dates reported by Biot are from the Chinese se 
1 shower.—The following seem to belong to eg 
aa i, Mar. 16, corr. to AD. 1850, Apr. 19-9. 
i # 2B “ 19°6. “ 
31, ‘“ “ “ 18-1. Chasles. 
ioe. ae 96, bd te eT. er 
1094, * “10; * “ eee | = 
1C S48 aL... ny Meee mY - ee yt a ye ee Ok 4 aot 
— “eer ge 4, corr, to Apr. 221. Chasles, 
