144 



Miscellaneous Intelligence. 



remarked, that the outward and inward armature times of the magnets 

 of the local registers, are relatively annulled by their having the same 

 value for the clock and signal electrolomes. 



According to Mr, Walker's report, these residual quantities, from 

 change of relative place of origin of the clock and signal waves, may 

 all be explained by the hypothesis that the time of propagation of the 

 galvanic wave from the place of the clock or star signal stations, to 

 that of the receiving register, though small, is not quite insensible. 

 A solution of the eighteen equations of condition formed on this hy- 

 pothesis, by Mr. Walker, give, for the velocity of the propagation of 

 the galvanic wave, through the compound circuit, eighteen thousand 

 eight hundred miles per second, with a probable accidental error, as 

 stated by him, of about one thousand miles. The statistics are too 

 incomplete to warrant any discrimination between the times of propa- 

 gation of the wave through the different kinds of media, viz., the wires, 

 the batteries, (three in number,) and the ground. After applying the 

 values of the wave-times by this hypothesis, and with this velocity in 

 the different portions of the whole circuit of one thousand and fifty 

 miles, no sensible discrepancy remains, the residual terms being not 

 greater than the probable errors, from the comparison of the two 

 Washington registers. All the readings now harmonize as well as if 

 all the clock and star signals, and all the printed records, had been made 

 in the same place. 



The result is one of much interest to the progress of science, and of 

 special importance in the longitude operations of the coast survey. 



The value apparently attributable to wave time, is too great to be 

 neglected in telegraph operations for longitudes intended to be used as 

 data in connection with geodetical measurements. A more extensive 

 series of operations, with more complete mechanical arrangements, 

 will be undertaken in the course of the coming season. 



Very truly yours, 



Dr. R. M. Patterson, Pres. Am. Philos. Society. 



Table of Relative Distances. 



A. D. Bache. 





Star Signal 

 Station. 



.Receiving 





.Relative miles trav- 





No. 



Station 



Wave Time. 



ersed by Clock and 







Compared. 





Signal Waves. 









1 



Philadelphia 



P-W 









2 





P-C 













3 





P-N 













4 





W-C 













5 





W-N 













6 





N-C 













1 



Cambridge 



P-W 



A-j-B+C - D 



150 



8 





P-C 



2B+2C 



900 



9 





P-N 



2B 



400 





10 





W-C 



-A+B-fC+D 



750 





11 





W-N 



-A+B-C+D 



250 





12 





N-C 



2C 



500 





13 



New York 



P-W 













14 





P-C 



2B 



400 





15 





P-N 



2B 



400 





16 





W-C 



2B 



400 





11 





W-N 



2B 



1 400 





18 



1 



N-C 















