820 TRANSACTIOyS OF THE AMERICAN INSTITUTE. 



triangular frame having two legs or posts firmly united at the top, 

 and another pivoted thereto at the point of junction. The two posts 

 just mentioned have provided thereon a sj'stem of gears and pullejs 

 working to wind and unwind a suitable rope upon a drum, also 

 carried upon such posts ; these latter being, furthermore, furnished 

 with two wheels in such a manner that when the frame is folded and 

 brought to a horizontal position it may be readily run upon such 

 wheels from place to place, while, when set upright, the frame will 

 •serve to sustain the mechanism just hereinbefore indicated, which 

 winds the rope in the operation of the machine. One feature of the 

 apparatus which called out approving remarks from several present 

 ;was the facility with which the gearing may be adjusted to proportion 

 the power to the speed, as circumstances may render expedient. 



New Screw Clamp. 



Pr. EoM'ell exhibited a screw clamp in which the screw works in 



,a nut formed with two movable parts held in position by means of 



springs. When it is desired to move the screw with facility for any 



distance it is released from the nut by compressing the springs which 



.hold, the latter thereto. 



Railway Bridge over the Susquehanna. 



M-V- Stetson gave a verbal description of the piers of the bridge 

 over the Susquehanna at Havre de Grace, and also the structure of 

 the bridge itself ; illustrating his remarks by means of diagrams on 

 the blackboard. 



Meteoric Stone. 



Dr.tL. Feuchtwanger exhibited some fragments of a meteoric stone 

 twhich fell in Warsaw, Poland, in January last. The stones were 

 round, he said, which showed that sometime elapsed in their falling. 

 There were over a million pieces of this meteor, found spread over 

 2,000 acres. He was about analyzing one of them. There are eight 

 vmasses weighing from 800 to 1,000 pounds. There was one stone of 

 5,000 pounds weight which fell previously in Mexico. 



New Tanning Material. 



Mr. Orville M. Tinkham exhibited specimens of leather, tanned by 

 means of a tanning solution derived from forest leaves. It has long 

 been kuown, he said, that there exists in forest leaves a certain amount 

 of tannic acid. Mr. Ira Wood, of Woodstock, Yt., has discovered that 



