CONTENTS. V 



Page. 



50. Meteorological Observations, 194 



51, 52, 53. Note to Dr. Hildreth's article in Vol. xxix. of this 



Journal — Eyes of flies changed to red by niti-ic acid — Death 



of Mr. David Douglas, . 196 



54. List of new publications, 198 



APPENDIX. 



On the collection of geological specimens and on geological sur- 

 veys ; by Charles T. Jackson, 203 



Confirmation of Judge Woodruff's account of the influence of the 

 Ash on the Rattlesnake; by William R. Morris, . . 208 



NUMBER II. 



Art. I. Observations on the Comet of Halley, made at Yale Col- 

 lege ; by Elias LooMis, ...... 209 



II. Observations on the Variation of the Magnetic Needle, 

 made at Yale College, in 1834 and 1835; by Elias 

 LooMis, ......... 221 



III. On the Transition Rocks of the Cataraqui ; by Capt. R. 



H. BoNNYCASTLE, R. En. 233 



IV. Theory of the Variations of the Arbitrary Constants in 



Elliptic Motion ; by Prof. Theodore Strong, . 248 



V. On Definitions ; by Rev. D. Wilkie, . . . 266 



VI. On the Formation of Compound or Twin Crystals ; by 



James D. Dana, 275 



VII. On the late efforts in France and other parts of Europe 

 to restore the Deaf and Dumb to hearing; by George 

 E. Day, late Instructor in the New York Institution 

 for the Deaf and Dumb, ...... 301 



VIII. On an instrument proposed for measuring the expansion 

 of Solid Bodies, and which may also be used as a Ther- 

 mometer ; by Lieut. W. W. Mather, U. S. Army, 324 

 IX. Notice of a Scientific Expedition ; by Prof. E. Emmons, 330 

 X. On two American Species of the Genus Hydrachna ; by 



James D. Dana and James Whelpley, . . . 354 

 XI. On the Resistance of Fluids, in reply to Professor Keely, 

 with remarks on the measure of Mechanical Power ; by 

 Eli W. Blake, 359 



