84 



THE TRANSATLANTIC LONGITUDE. 



from Valencia, and increased by this amount for signals from Newfoundland. This 

 interval is a measure of the longitude, uncorrected for clock-errors or for transmis- 

 sion-time; but for our present purpose its absolute magnitude is unimportant, since 

 our inquiry is answered by comparing the results deduced from positive and from 

 negative signals with each other. Any excess of the time consumed in the passage 

 of either class of signals should manifest itself by a superior value in the measures , 

 of the temporary clock-difference derived from that class, when the signals are sent 

 westwardly. For eastward signals the reverse holds. 



It had been intended, as will be seen from the original programme, to measure 

 the velocity of signals while the batteries at both ends were included in the circuit, 

 as well as when only one was employed ; but since the construction of the signal- 

 keys rendered this arrangement difficult, and inconvenient in many respects, the 

 plan was not carried out. In all cases the battery at the receiving station was 

 cut off from the circuit. Consequently all our experiments may, so far as regards 

 the point now in question, be arranged in four classes, according to the character 

 of the ground-connection. When, as in the last three of these classes, both cables 

 were included in the circuit, those signals are called positive which put the copper 

 of the Valencia battery to the cable of 1865, or the copper of the Newfoundland 

 battery to the cable of 1866. 



A. Cable of 



18fj'5, ONHY, USING CONDENSERS. 









From Positive Signals. 



From Negative Signals. 



No. 



Excess for 





No. 



Mean interval. 



No. 



Mean interval. 



cells. 



positive. 



Valencia signals. 



October 25, Longit. 



30 



2" 62" 9».041 



28 



2h 52m gs Q4J 



10 



O'.OOO 



28, 



29 



10.107 



30 



10.120 



10 



—0.013 



Newfoundland signals. 















October 25, Longit. 



30 



io.2n 



29 



10.293 



10 



—0.016 



28, 



28 



11.110 



27 



11.096 



10 



+ 0.014 





From 

 No. 



Positive Signals. 

 Mean interval. 



From 

 No. 



Vegative Signals. 

 Mean interval. 



No. 

 cells. 



Excess for 

 positive. 



Valencia signals. 



November 10, I. 1, 

 10, II. 1, 

 16, IV. 1, 



Newfoundland signals. 



16, IIL 1, 



8 

 8 

 8 



8 



2'' 52"" 20^862 

 20.887 

 21.179 



22.234 



9 



9 



10 



8 



2" 52" 20^844 

 20.864 

 21.163 



22.262 



4 

 4 

 4 



4 



+ 0».018 

 + 0.023 

 + 0.016 



+ 0.028 





C. 



Both cables ; zincode to ground. 











From 

 No. 



'ositive Signals. 

 Mean interval. 



From 



No. 



Negative Signals. 

 Mean interval. 



No. 

 cells. 



Excess for 

 positive. 



Valencia signals. 

 November I, 

 10, 

 10, 



I. 2, 



1.2, 



II. 2, 



9 

 9 



7 



2" 52°'14M19 

 20.692 

 20.693 



9 

 10 



9 



2" 52'°14M24 

 20.869 

 20.850 



20 

 4 

 4 



—O'.OOS 

 —0.177 

 —0.157 



Newfoundland signals. 



16, III. 2, 



9 



22.290 



10 



22.315 



4 



+ 0.025 



