237 



Journal of the Franklin Institute of the State of Pennsylvania. Third 

 Series. Vol. IV. No. 5. Philadelphia, 1842.— From Dr. Pat- 

 terson. 



FOR THE CABINET. 



An Inkstand of a new construction, invented by Mr. George Bar- 

 nam. — From the Inventor, by the hands of Mr. Baldwin. 



Mr. Lea mentioned that, by some inadvertence, he had used, 

 in his papers read before the Society, several specific terms 

 which were preoccupied. He proposed to change on that ac- 

 count 



Melania rufa to Melania rvfescens. 



M. striata to M. striatula. 



M. lavigata to M. lesvis. 



M. corrugata to 31. rugosa. 



Mr. Lea also mentioned, that he proposed the provisional 

 name of pressus for a Unio which he called compressus in a 

 paper read before the Society, until it should be ascertained 

 whether or not the shell from the Tilgate beds (secondary for- 

 mation in England,) called by Mr. Sowerby, Unio compressus, 

 should prove to be a true Unio, of which he had great doubt. 



Professor Bache communicated, orally, a description of a new 

 induction inclinometer, by Professor Lloyd, of Dublin, and 

 suggested a modification, by which the same instrument might 

 be used to measure changes of declination and inclination. 



In this new instrument of Professor Lloyd, the magnetism deve- 

 loped by the earth in a soft iron bar, placed vertically, is made to act 

 upon a magnetic bar suspended in a horizontal position ; the changes 

 of inclination being deduced from the changes in the position of the 

 horizontal bar. The modification proposed by Prof. Bache would, 

 he conceived, be useful, when it was desirable to economize in the 

 outlay for instruments, and when the director or a skilful assistant 

 was the observer. Two pieces of soft iron are so placed on the op- 

 posite sides of the horizontal magnetic bar as not to change its posi- 

 tion, one of them occupying the place of the vertical bar of soft iron 

 in Professor Lloyd's instrument. By an obvious mechanical arrange- 

 ment, the position of one of the pieces of soft iron is changed in a 

 vertical line ; so that a pole of different name comes into the horizon- 

 tal plane of the axis of the suspended magnet, which is now deflected 



