REPORT OF THE SECRETARY. 15 



III. Meteorological observations made at Providence, Rhode Island, 

 for 28i| years, by Prof. Alexis Caswell. 



IV. Meteorological observations made near Washington, Arkansas, 

 for 20 years, by Dr. Nathan D. Smith. 



V. Researches upon the venom of the rattlesnake,, with an investi- 

 gation of the anatomy and physiology of the organs concerned, by 

 Dr. S. W. Mitchell. 



1. The first of the papers mentioned above forms the third part of 

 the series of memoirs on the results of the observations of Dr. Kane, 

 during the second Grinnell expedition. An account of the first and 

 second numbers of the series, relating to magnetism and meteorology, 

 has been given in the two preceding reports. The third, or present 

 paper, gives the discussions and results of the astronomical ob- 

 servations which were made, principally at Van Rensselaer harbor, 

 the winter quarters of the expedition during 1853-54-55. These 

 observations were under the especial care of Mr. August Sonntag. The 

 principal instruments employed were two sextants by G-ambey, divided 

 to ten seconds, a theodolite, a transit instrument, and five mean time 

 chronometers. The observatory consisted of four walls of granite 

 blocks cemented together with moss and frozen water. The transit 

 and theodolite were mounted on piers formed of an extemporaneous 

 conglomerate of gravel and ice, well rammed down into iron-hooped 

 casks, and afterwards consolidated by water. Thus constructed, they 

 were found to be as firm as the rocks on which they rested.. 



The first observations for latitude were made with the theodolite, 

 and later ones by means of a sextant and artificial horizon, on the 

 moon and moon-culminating stars. The time was noted by a 

 pocket chronometer. The instrument was properly adjusted in posi- 

 tion, but in consequence of the high latitude and the extreme cold, 

 this was a very difficult operation. The angle of elevation was, in 

 many cases, observed by the reflection of the image of the object from 

 a mercurial horizon ; the bubble of the level having been rendered 

 useless by the extreme reduction of temperature to which it was 

 subjected. 



Observations were also made on occultations and eclipses^ namely : 

 the occupation of Saturn, December 12, 1853 ; of the same planet, 

 January 8, 1854, and February 4, 1854; of Mars, February 13, 1854; 

 and on the solar eclipse of May 15, 1855. In the occultations of 

 Saturn, the disappearance and reappearance of the more prominent 

 points of the ring were accurately noted, and the results have been 

 elaborately discussed by Mr. Schott. From all the observations, the 



