348 MEMOIRS OF THE AMERICAN ACADEMY. 



ERRATA ET ADDENDA. 



It was intimated, on page 12, that Mairan had been, probably, led into some mistakes and had duplicated 

 some auroras by reducing again to new style dates which were originally given in new style. The following 

 cases are sufficiently clear. 



The aurora of .March 17, 1707, is the same as that of March 6. 



The aurora of December 7, 1710, is the same as that of November 2G. 



The aurora of May 1, 1716, is the same as that of April 20. 



The auroras of May 2, 3, 4, and 5 should be changed to April 21, 22, 23, and 24. 



The aurora of March 15, 1718, is the same as that of March 4. 



The auroras of March 5 and 6, 1719, are the same as those of February 22 and 23. 



The aurora of April 9 is the same as that of March 29. 



The aurora of April 18 is the same as that of April 7. 



The aurora of October 27 is the same as that of October 16. 



The aurora of November 14 is the same as that of November 3. 



The aurora of November 17 is the same as that of November 6. 



The aurora of November 24 is fhe same as that of November 13. 



The aurora of December 1 is the same as that of November 20. 



The auroras of April 10, September 25, October 30, November 22, should be carried back by 11 days. 



The aurora of February 26, 1720, is the same as that of February 15. 



The aurora of December 10 is not found in Frobes. 



The date of September 23?, 1721, should be changed to September 28. 



Mairan has not altered Frobes's dates for February, 1721, but all the others for 1721, and all for 1722 

 and 1723, have been advanced by 11 days, as if they had been given by Frobes in old style. There is no 

 obscurity in the mattei after January 1, 1724.* 



Is the aurora of January 20, 1728, in Frobes's work? 



The auroras which Frobes and Mairan assign to April 6, 9, 10, and 11, 1717, are probably the same as 

 those of January 6, 9, 10, and 11 of that year. See Mem. de l'Acad. Paris, 1717, p. 3. 



There are some discrepancies between the dates of auroras given by Dalton in his Meteorological Observa- 

 tions and Essays and his record in the Manchester Memoirs, Vol. V. p. 666, &c. 



On page 23, for 1757 read 1657. 



On page 25, note 9, for II. 566 read I. 566. 



On page 26, the aurora which Boue assigns to November 3, 1719, is probably the same as that of 

 November 14. 



On page 26, I have given the date of December 22, 1719, to the first aurora seen in New England, on 

 the assumption that the date of December 11, as given in the Mass. Coll. and by Felt, is in old style. I 

 should add that Trumbull and Holmes place this aurora on December 17. 



On page 27, against the aurora at Lynn,, for September 23, 1721, read September 28. 



On page 29, against the auroras at Upsal, for September 6, 9, and 11, 1725, read February 6, 9, and 11. 

 Acta Lit. Sueciae., II. 141. 



* For auroras of 1719, see Rozier, Observ. sur la Physique, XV. 134. 



