VOL. LIX.j PHILOSOPHICAL TRANSACTIONS. 677 



between St. Paul's and Greenwich, which is 22-i^% it will give 2'" 24-^." of time, 

 for the difference of longitude between the round tower at Windsor castle, and 

 the Royal Observatory at Greenwich. 



Mr. H. observes, that the only inconvenient circumstance, during the time 

 of observing the transit, was the wind; which, blowing rather hard, and di- 

 rectly into the telescope, together with the smallness of the sun's altitude at that 

 time, made the limb so very ill defined and undulating, that it is possible there 

 may be an error of 5 or 6 seconds, at least, in the time of the external contact; 

 being anxious therefore of having the internal contact as exact as possible, he 

 changed the magnifying power of^ the telescope from that of 125 times to that 

 of 55 times, the least of all, which succeeded beyond expectation; for by this 

 means that undulating motion of the sun's limb was greatly reduced, though not 

 entirely taken away, appearing much better defined than before, as did likewise 

 that of the planet Venus; insomuch that the error, if any, in the time of the 

 internal contact, by which is meant the completion of the thread of light formed 

 by the sun's circumference, cannot exceed 3 seconds. The observing of the 2 

 contacts with so different magnifying powers as that of 125 and that of 55, 

 must occasion some difference in the times, and duration between the 2 contacts, 

 from what they would have been, had they both been observed with the same 

 magnifying power; which is to be allowed for. 



By the clock. Mean time. 



External contact of Venus with the sun 7^ 4'" 30'. . 7^ 6" 14' p.m. 



The internal contact at 7 22 38 . . 7 24 22 



Duration between the contacts, the clock being 



1 ■" 44' too slow for mean time O 18 8 



Venus's diameter measured 3 different times O 5Q-^^ 



LXI. An Attempt to Elucidate Two Samnite Coins, never before fully, ex- 

 plained. By the Rev. John Swinton, B.D., F. R. S. p. 432. 

 The first of the coins Mr. S. proposes to consider here, is a Samnite denarius 

 of Papius Mutilus, published by Sig. Olivieri and M. Pellerin, with the word 

 SAPiNiM on the reverse, in Samnite-Etruscan characters ; an interpretation of 

 which has, as he apprehended, been ineffectually attempted by the Marquis Scipio 

 MafFei, Sig. Olivieri, Sig. Avvocato Passeri, and M. Pellerin. The other has 

 the initial letter of the name of a town on the reverse, indicating the place 

 where it was struck. These pieces are of a species different from that of the 

 coins of Papius Mutilus, Tiberius Veturius, andNi. Luponius, of which Mr. S. 

 has largely treated in some of his former papers. The first species appertains to 

 cities, the other to the Samnite, or Italian, commanders, whose names they 

 bear, for the most part, on the reverse. Hence it seems, at first sight, ex- 



