NUMBER CXLII. 



Art. XXV.— Notes on Physiological Optics. No. 5. Vision 



by the Light of the Electric Spark ; by W. L. Stevens, 



XX VI.— Crystals of Monazite from Alexander County, North 



XXVII. — Occurrence and Composition of some American 



varieties of Monazite ; by S. L. Penfield, : 



XXVIII.— Irregularities in the Amplitude of Oscillation of 



Pendulum*; by C S. Peirce, 



XXIX.— Stresses caused in the Interior of the Earth by the 



Weight of Continents and .Mountains; by G. H. Darwin, 

 XXX.— The Deerneld Dyke and its Minerals; by B. K. 



Emkksox, 



XXXI.— Occurrence of Siphonotrctu Scotica in the Utica 



Formation near Ottawa, Ontario; by J. F. WillTEAYES, : 

 XXXII.— A recent species of Ileteropora from the Strait of 



JuandeFuca; by J. F. Whiteaves, ! 



XXXIII.— Notes on interest he _r Minerals oecurrin.;- near Pike's 



Peak, Colorado ; by W. Cross and W. F. Hillebuand, ! 





un Organo finora non avertito .ii aleuni K 

 an Society Aiu.b -^ .-t tli. ..-h <.t I piphwic 

 -real I'omuof September. Iss2: Atiales <le 



Fish and Fisheries, S. 



