— 134 — 



« Inoltre tenendo presente l'equazione (23) (mem. cit.) si vede che cinque posizioni 

 forniscono l'equazione di controllo 

 60 t 



■ = 18mn -+- 54m 23 -4- 18m 34 — 9m 13 — 9m 24 -+- 2mi 4 



u 



= 18w 2 3 -*- 54m 34 -+- 18m 4 g — 9m 24 — 9m 3 5 -+• 2m 2 s . 



« Gli sviluppi che hanno servito a dare le equazioni (43) (44) e (45), applicati al 

 caso presente, e fatti in guisa da farvi figurare il raggio vettore relativo alla terza 

 posizione, danno per risultato 



^2 fi 



6ikt l p cos i —5 — = 152tn 23 -t- 152m 3i — 90m 12 — 90m 43 — 102m 24 



f 13 



+ 29m 13 -i- 29m 35 — 10m u — 10m 2 5-<-6m g . 



In questa equazione k è la costante di Gauss relativa al sistema binario che si con- 

 sidera, t l'intervallo di tempo fra le successive cinque posizioni, che sono equidistanti, 

 p il semiparametro, i l' inclinazione del piano dell'orbita satellite al piano che è nor- 

 male al raggio visuale diretto al sistema, ed r il raggio vettore. Un secondo gruppo 

 ed un terzo di cinque posizioni ognuno forniranno i valori di 



fri fi ] { <i fi 



64/ci v p cos % — 5 — , 64ktV p cos i—s — 



r 23 r 33 



e si avranno quindi i rapporti dei raggi vettori n 3 r n r 33 ». 



Astronomia. — Jenkins, The Barometric curve at London for 100 Years. 

 Presentata dal Socio Blaserna. 



« I desire to lay before the Academy a very startling conclusion I have arrived at 

 on comparing the barometric curve of London with the curve which accompanies 

 my paper On the connexion between rneteorological phenomena and the Urne of 

 the arrivai of the earth at perihelion (Transunti, ser. 3\ voi. IV pag. 172). 



« It is this ; the earth itself forecasts its weather a year in advance, and in some 

 cases two or even three years in advance. It will be remembered that the latter of 

 the above- mentioned curves was constructed by tabulating the ti me the earth arrived 

 at perihelion each year, sometimes late, sometimes early. This irregularity, as is 

 well-known, is due to the attraction of the other planets. Now I find that it is visited 

 upon the inhabitants of the earth in the form of weather, and that the barometer 

 is a faithful recorder of this irregularity. 



« I am preparing a paper, which I hope to present to the Academy at its next 

 sitting, in which I shall shew that our English weather (which is held to be so 

 capricious), and indeed ali weather, is really only the regular manifestation of a 

 great naturai law. 



« It necessarily results, if the barometer follows the perihelion-curve (since this 

 curve can be astronomically calculated any number of years in advance), that our 

 weather is being forecast years in advance at the Eoyal Observatory at Greenwich. 



« I shall be able to show that our weather moves in a certain measure in a 

 cycle of 8 years, in a greater degree in cycles of 12 and 24 years (the latter due 

 to the 8-year cycle of Venus and the 12-year period of Jupiter), and in a greater 



