t *37 ] 
VIII. Agronomical Ohfervations . In two Letters, from M. 
Francis de Zach, Profeffor of Mathematics , W Member of 
the Royal Academies of Sciences at Marfeilles, Dijon, and 
Lyons, to Mr . Tiberius Cavallo, F. R . & 
Read December 23, 1784. 
S IR ( Lyons, April 4, 1783. 
T SEND you the account of the ohfervations on the eclipfc 
JL of the moon, which I have made together with the rev. 
Father le Fevre, Aftronomer at Lyons, in the Obfervatory 
called au grand College ; to which I Riall add the ohfervations of 
the vernal equinox ; fome ohfervations on Jupiter s fatellites, 
made at Marfeilles by M. Saint Jacques de Sylvabelle ; 
and, laftly, a new folution of a problem that occurs in com- 
puting the orbits of comets. If you think that thefe obferva- 
tions do in any way deferve the notice of the Royal Society, I 
Ihall be very glad you would communicate them. In order to 
afcertain the going of the pendulum clock, 1 took feveial cor- 
refponding altitudes of the fun, which you will find in the fol- 
lowing table. On the day of the ecliple the Iky Was very 
ferene, nothing could be filler, and it continued fo duiing the 
obfervation. I determined to ufe an achromatic telefcope or 
3I feet length, that fhews objects in their natural pofition, be- 
caufe the diluted and uncertain termination of the true fhadow 
of the earth appears more perfectly defined by fmall than by 
Vol, LXXV. T large 
