Erratum

The external contact was observed At $21^{\text{h}}\ 22^{\text{m}}\ 53^{\text{s}}$ with a telescope of 6 feet. $21^{\text{h}}\ 22^{\text{m}}\ 50^{\text{s}}$ - - - - - - 8 feet. $21^{\text{h}}\ 22^{\text{m}}\ 59^{\text{s}}$ - - - - - - 11 feet. Professor Canterzani examined the observations by projection, and found them to agree very nearly with those made in the upper chamber by Signor Zanotti. END of PART I. ERRATUM. Page 198, Line 11, for from, read with. ERRATUM in Vol. LI. Part II. Page 922, Line 2, for sum or difference, read difference or sum.