os^ .. ;..,,.„ 



l!^^ ... „,,. .. ..^ . , PLATES. 



TO '^;jk:i.n j 



^ I. Illustrative of Prof. A. Connell's Paper on a new Hygrometer or 

 ,-, , Dew-point Instrument, and Prof. Gerling's Description of two 



'^'''' Letter-scales. 



II. Illustrative of M. G. Wertheim's Paper on the double Refraction 

 %*X^ temporarily produced in Isotropic Bodies; and of Dr. Barry's 



Paper on the Origin of the Cell-Membrane, and the Nature of 

 the Earliest Pores. 



ERRATA. 



Page 308, line 17 from top, for P. hina, an unnamed species &;c. read 



P. ? an unnamed species &c. 



Page 3.36, line 7 from top, /or September read November. 





