150 



den's additional papers relative to the Trigonometrical Survey 

 of Massachusetts, reported in favour of their publication in the 

 Society's Transactions, which was ordered accordingly. 



Prof. Vethake announced the death of Philip H. Nicklin, 

 one of the Counsellors of the Society, which occurred on the 

 2d of March, at the age of 55; accompanying the announce- 

 ment with appropriate remarks in relation to the character and 

 services of the deceased: whereupon the Society appointed 

 Prof. Vethake to prepare a necrological notice of Mr. Nicklin. 



A communication was presented by Prof. A. D. Bache, on 

 behalf of Lieut. J. M. Gilliss, U. S. N., exhibiting the monthly 

 means of the magnetic declination, the barometer, and the ther- 

 mometer, as observed by him at the Washington Observatory. 

 This communication was referred to a committee. 



Mr. Lea stated that specimens of the Melania Altilis, de- 

 scribed by him, and supposed hitherto to be a southern shell, 

 had recently been found by his son on the shore of the Schuyl- 

 kill, near this city. 



Dr. Goddard presented specimens of Daguerreotypes on a 

 surface of gilded silver, and stated that the surface of iodide 

 of gold was more susceptible to the Daguerreotype action of 

 light than that of the iodide of silver, that the surface of the 

 plate might be polished without injury before the action of the 

 iodine, and that the lights came out better than on the silver 

 surface. 



Major Bache remarked upon a theory presented by certain 

 geologists, that the coral reef owes its permanence to vital 

 forces, stating his conviction that this was rather owing to a 

 general law by which vertical dikes, based below the depth of 

 the action of the waves, opposed no resistance to their motion, 

 and were not, therefore, destroyed. He stated that this fact had 

 been observed by engineers, and used in most of our public 

 works on the lakes, and that he had drawn a similar inference 

 from observations made by him at Mount Desert Island in 1822. 



Prof. A. D. Bache exhibited the curves representing the re- 

 sults of the bi-hourly magnetic observations, made during the 

 years 1S40 and 1841 at the Girard College Observatory, show- 

 ing the daily changes of magnetic declination, and horizontal 

 and vertical intensity. He stated that from these curves the 



