8 



avoidrtble Interruptions. The most important of these interntptions 

 was one of seven montlis, from March to Sept., 1851, at which time 

 Mr. Herrick was attacked by a fit of sickness so severe that it was 

 not Supposed that he could survive it. After this sickness he never 

 fully recovered his former physical vigor, and this consideration com- 

 pelled him to abandon his systematic register in 1854. 



During these seventeen years, it was Mr. Herrick's invariable cus- 

 tom to go out into the oj^en air at several different times each evening, 

 in order to see whether any traces of auroral light could be detected, 

 and the result of his observations was entered in his register. When- 

 ever an aurora was seen, a brief description of its principal features 

 was given. He however regarded it as of almost equal importance 

 that the record should show iipon what nights 7io auroral light could 

 be seen ; also how far observation was interfered with by moon-light, 

 clouds, haze, etc., and on what nights observation was from any 

 cause rendered impossible. 



In the printed register, we have generally allowed but one line to 

 each evening. Whenever the record required a larger space, the re- 

 mainder is given at the bottom of the page, and this addition is indi- 

 cated by an asterisk inserted in the corresponding line. 



Whenever any auroral light was seen or suspected, we haA'e not 

 felt at liberty to abridge the record, since Mr. Herrick was scrupu- 

 lously careful in his choice of expressions ; but when no light Avas 

 suspected, we have abridged his descriptions of the state of the sky, 

 so as to reduce them to the limits of a single printed line. 



The numbers in parentheses at the ends of the lines are intended 

 to indicate the auroras actually seen at New Haven. Xo fixed rules 

 could be followed as regards including or excluding suspected auro- 

 ras. Those cases which have been included correspond, however, 

 with but few exceptions, to Mr. Herrick's own judgment as indicated 

 in a numerical summary of all his observations, M'hich he furnished 

 to one of the committee a few years before his death. 



The following abbreviations are used for words of frequent occur- 

 rence. Entries made in the Register by Mr. Herrick upon the author- 

 ity of Mr. Francis Bradley are marked (F. B.). 



A.B., 



ac't, 



aft., after.. 



alt., 



al't, 



betw'n, 



c'd, 



cert., 



cl'ded, 



cl'ds, 



cl'ss, 



cl'r, 



d'y, 



det., 

 d'g, 



obscured, 

 occasional, 

 occasionally, 

 possible, possibly, 

 p., prob., probable, probably, 

 partlj'. 

 rainv. 

 slight, 

 slightly, 

 suspected, 

 twilight, 

 uncertain, 

 visible, 

 ■wholly. 



