306 MEMOIRS OF THE AMERICAN ACADEMY. 



Pays-Bas, Buys Ballot. After I had found these manuscripts in the library of the 

 University of Leyden, every facility for consulting them was kindly granted by the 

 librarian, Dr. W. G. Pluygers, and by his assistant in charge of the manuscripts, 

 W. N. du Rieu. From this source I have gathered the observations made in Holland 

 on seven hundred and eighty-four auroras, most of which have never been published 

 before. The observations on the aurora in Holland, in Brunswick, Maine, etc., are 

 printed here as a supplement to my second catalogue of auroras. 



SUPPLEMENTARY CATALOGUE. 



I. Observations on the Aurora, made by Musschenbroek, at Utrecht, etc. 



1728. Feb. 7-. 9-, lit, 13-; March 20-, 30-; April 2; 9-, 12-; Aug. 31-; Sept. 30- ; Oct. 2; 1; 12-, 29-, 

 30- ; Nov. 2; 23-. 



1720. March 27', 28-; Oct. 21- ; Nov. 16*. 



1730. Feb. 15-; March 6' ; April 13-; Sept. 10-; Nov. 5-, 6. 



1731. March 7- ; April 3-, 13 ; May 14- ; Oct. 2; 3; 7; 8; 23- ; Nov. 6-, 30-. 



1732. Feb. 18- ; March 21-, 27- ; May 27, 28, 30 ; Aug. 22- ; Sept. 27- ; Oct. 22-, 23- ; Nov. 10, 12-, 19, 

 20-, 21. 



1733. April 18, 19- ; May 4, 7, 16-, 17 ; Sept. 5, 6' ; Oct. 10-, 15 ; Nov. 7- ; Dec. 23. 



1734; Feb. 3 ; March 22 ; April 1; 8-, 9- ; May 1-, 4-, 5-, 6-, 24-, 25-, 20-, 27-, 28-, 29-, 30-, 31" ; June 1, 

 2, 4, 5, 7, 24- ; July 5-, 6, 7- ; Aug. 3, 7-, 9 ; Sept. 5, 10, 21-, 25-, 27-, 29- ; Oct. 1-, 2; 5-, 6-, 14- ; Dec. 

 19-, 25*. 



1735. Jan. 23, 26- ; Feb. 11, 22-, 23 ; March 1, 2; 1G, 17, 19, 22-, 23-, 24-, 25-, 26-, 27, 28, 29, 30 (dubiu) ; 

 April 20' (from 8 h to 9 h ), 22- (clara : from 11 p. m. to 1, coruscans), 23' (clara) ; May 14, 17, 18, 19, 22; 

 June 9, 10, 11, 13, 14 ; July 2, 3, 8, 10, 17 ; Oct. 24- ; Nov. 10, 11, 14- ; Dec. 11, 21. 



1736. Jan. 22-, 31 (tranquilla) ; Feb. 2 (placida in nubibus) ; March 3 (exigua), 15'; April 3' (placida), 

 5', 11 (placida), 14- (placida), 27; May 4- (clara), 5 (exigua), 6 (placida), 11 (placida), 14 (magna, tran- 

 quilla), 15 (placida), 27 (placida) ; June 1, 2 (magna), 23 (magna), 24 (magna), 29 (magna), 30 ; July 25 ; 

 Aug. 13- ; Sept. 3-, 5- (placida), 9- (coruscans), 25- (placida), 27-, 28, 29- (magna, placida) ; Oct. 1- 4-?, 6' 

 (exigua, placida), 7- (magna), 10- (magna, tranquilla), 11, 12, 20-, 25-, 26' (magna), 27- (maxima), 28- 

 (exigua), 29-, 30- (obscura), 31 ; Nov. 1 (obscura), 7', 8- (maxima), 10 (levis), 11, 12, 18-, 20, 21, 24-, 25-, 

 26 ; Dec. 6, 15, 18- (magna, coruscans), 29, 30. 



1737. Jan. 4, 19-, 29-, 30-, 31- ; Feb. 2; 20, 28- ; March 1, 4 (inconstans caelum), 8 ; May 3 ; June 4, 5, 

 17, 18, 23. 21 ; July 26 (tranquilla) ; Aug. 21* (magna, coruscans), 22- (magna), 26 (exigua), 27, 28; Sept. 

 17, 19 (placida) ; Oct. 1«? 17, 18, 30 ; Nov. 19, 20 ; Dec. 5; 15 (caeli rubido), 16-, 1 18, 26, 28-. 



1738. Jan. 25- (magna, coruscans), 26; Feb. 8 (exigua), 9, 12-, 18 (magna), 19- 24, 26 (placida) ; March 



1 Die 16° vesperi totum caelum rubicundum et lucidum fuit ab hora 6 ad 11 et ultra; postea, novelb's publicis vidi in 

 plurimis Europae locis Auroram Borealem observatam. 



