198 C. L. Dresser on the Conducting Powers of Wires 



on each side, we infer that it is there the antagonistic resistance 

 more effectually overpowers the momentum of the central mass*. 



Ideal of upheaval. 



Entertaining the idea that all these contortions are super- 

 ficial and contemporaneous, and the result of a leverage from 

 below more uniform and of much wider extent, we hasten to the 

 conclusion, that the protrusion of the Wealden beds through the 

 chalk, and of the chalk through the tertiaries in this line of ele- 

 vation, extensive as it is, is only a part of a much greater whole. 

 We shall revert again to this consideration in the sequel. 

 [To be continued.] 



XXIX. Eocperiments on the Conducting Powers of Wires for Vol- 

 taic Electricity. By C. L. Dresser, Esq.-\ 

 THE instrument used in these experiments was the glass 

 thread galvanometer of Ritchie, described in the Philo- 

 sophical Transactions J. This instrument, though one of the 

 most perfect kind, easy of construction, well adapted for the 

 measurement of electro-magnetic forces, and extremely accurate, 

 has not received that attention from scientific men to which the 

 facility of its use entitles it. Requiring no calculation, a vast 

 number of experiments may be read ofi" in rapid succession. 



A few alterations were made in its construction. 



1. The graduated card placed under the needles was discarded 

 as being no measure of the forces exerted, and a plain card with 

 a black mark under the centre of influence of the conducting 

 wires substituted. To this mark the needles were carefully ad- 

 justed at every experiment. 



* It is not to be supposed that we mean by this, that the Downs quoad 

 Downs had any share in this resistance, but only that the central impulse 

 gradually fading in the distance is there more successfully resisted. Tiie 

 long synclinal that extends with but little interruption northward from 

 Hindhead, terminating in the sudden flexure of Peasemarsh and the Hogs- 

 back, is strongly illustrative of the antagonism here spoken of. 



t Communicated by the Author. 



X Philosophical Transactions, 1830, p. 218. 



