Scientific Intelligence. 



rentv seconds. This could only 1 



ctio'n from a series of surfaces pi 



• i>f the material of the a 



ine of probabilities) would not 



construction of these instruments appears in Nature for Nov. 30th, 

 1876 (xv, 101). For some time after the introduction of subma- 

 rine telegraphy the mirror galvanometer was the only instrument 

 delicate enough to receive the messages transmitted through a 

 long cable. The clerks must here read the message by watching 

 the deviations of a spot of light from side to side. The siphon- 

 recorder serves to draw a sinuous line by which the message is 

 recorded in permanent form. The speed of sending will be greatly 

 increased by sending alter each current a seconcTin the opposite 

 direction. This is effected by the curb-sender. Three rows of 

 holes are punched in a long strip of paper, the central row serving 

 to carry the paper through the machine and the row on one side 

 corresponding to the dots or positive currents, that on the other 

 to the lines, or negative currents. When the paper passes through 

 the machine it receives by clock-work a uniform motion. Two 

 prickers are placed so as to correspond to the two outer rows of 

 holes._ When a hole passes, the corresponding pricker falls into 



it, and 



™ "wheel S 



litis a spring 



through an opening in the 



■im of; 



iv\olvi 





The spring 



being caught in the rim 



of the 



wheel 



s obliged 



o remain the 



re until the wh 









nd the open 





free it 



The wheel makes 



one revolu 





SeS th( 





When the spring is 



ie rim of the 



viueli 







>etween the battery and another set of 



- 







t is sent throi 



gh the cable, and shortly 



aft. r i 







is sent hi the 



opposite direction. The" 





are rev 



>rsed when 



the other pri 



=ker acts. & 



C. P. 





IL 



Geology a 



xd Mineralogy. 





1. Report on the Transportation route along the Wisconsin and 

 !' Rir,r, /,/ '/, V t, , r Wis,;,,,*!,,, bet.ii. en tin 

 River and Lake Michigan; by Gouvbrneur K. Waukkx, 

 Major ot Engineer- and iirevet Major General, 17. S. Army. 114 

 pp. Svo, with many maps. Senate Ex. Document, No. 28, 44th 

 ( 'i- f '" >'> ishmgion. 1-7 (,.„,, , \\ U1 „\ Report gives, 

 - v -tory of geographical knowledge and surveys respecting 

 ransportation route, then an account of the w 

 done by him or under his direction. We take the fol- 

 lowing facts from it. 



The two streams— the Fox River which joins Lake Michigan at 



