INDEX. 



397 



unguispinus, 278. 



viridescens, 275. 



Whipple!, 271. 



Wislizeni, 274. 

 Echinocereus radians, 280. 



Effluvia, ashes, &c., emitted by volcanoes, nature of, 337. 

 Elastic sacs, the forms assumed by, 8, 10. 

 Electrical currents, the induction of, 198. 

 Ellipse, the property of, 10. 

 Engelmann, George. Synopsis of the Cactacse of the United States, 



259. Geography of the Cactus region of the United States, 311. 

 Epidemics, cause of, 35. 



Equation, personal, on the means of diminishing the, 47. 

 Ericsson engine, on the, 28, 31, 33. 



EusTis, H. L. On the property of the ellipse, 10. Formula for the 

 measure of the solidity of a prismoid, 22. On a case of warped 

 surfaces, 251. 

 Everett, Edward. Changes in the locality of the solfa-taras, 337. 



F. 



Fall of Troy, two distinct dates of, 382. 

 Families, similarity of form essential, 379. 

 Farrar, John, decease of, 38. 

 Fellows elected. 



Adams, Charles Francis, 356. 



Arnold, Albert N., 205. 



Boutwell, George S., 356. 



Brewer, Thomas M., 167. 



Gary, Thomas G., 257. 



Child, Francis J., 205. 



Choate, Rufus, 167. 



Clark, Henry James, 326. 



Cooke, Josiah Parsons, 32. 



Cotting, Benjamin E., 59. 



Curtis, B. R., 167. 



Dexter, William P., 24. 



Durkee, Silas, 167. 



Ellis, George E., 257. 



