220 



lection now on the table there are good specimens of the lower valve, 

 as well as characteristically-marked upper ones. 



2. On the " Fossil Echini^ of lire. — Dr Fleming stated, that 

 having found plates of Ure's Echinus in company with fragments of 

 spines, with proximal extremities, similar to the figure, Tab. xvi., f. 

 8, and the distal denticulated extremities conjoined, he had character- 

 ised the species in his " British Animals," denominating it Cidaris 

 Urii, thereby commemorating the labours of the discoverer. Captain 

 Portlock, in the work already reported, has described and figured 

 portions of, apparently, the same species, as Cidaris Benburbensis, 

 manufacturing new species besides, without being aware of the dif- 

 ferences in the form of the spines, as well as in the sculpture of the 

 plates, from different parts of the crust ; truths illustrated by the 

 existing British Cidaris papiUata, giving evidence to the palae- 

 ontologist of the expediency of combining a knowledge of recent with 

 extinct forms. Dr Fleming concluded tliis notice with stating that 

 he found, during last autumn, the remains of this carboniferous lime- 

 stone organism in the lowest bed of the old red sandstone sei'ies, on 

 the Berwickshire coast, in which he detected marine remains, begin- 

 ning at the fundamental conglomerate, where it rests on the '' Transi- 

 tion Rocks" at the Siccart Point, and proceeding westward to Dunbar. 



4. Notice by Professor Piazzi Smyth of Locke's Electric 

 Observing Clock. 

 This instrument, which has been invented in America, consists of 

 an electro-magnetic machine, which, being placed in connection with 

 an ordinary astronomical clock, does not interfere with the regularity 

 of its going, while it marks the instant of each vibration of the pen- 

 dulum on a revolving cylinder, whose circumference moves at the rate 

 of one inch per second. Two wires being then taken to an observer 

 at any distance, if he, when he observes a star crossing the meridian- 

 wire of his telescope, makes contact with the wires, that moment is 

 immediately marked on the same moving cylinder where the even se- 

 conds are registered. The fraction of a second may be then obtained 

 with as much accuracy as the space of an inch may be subdivided by 

 ordinary mechanical means : say to the hundredth of a second. This 

 method is further available in many cases where the present mode of 

 noting transits is not, and admits of a great multiplication of obser- 

 vations during the short space of time that the star occupies in cross- 

 ins the field of view. 



