579 



possession of the whole line, or either of its sections. The needle is 

 deflected on the side marked " up " or " down," according as the 

 current collected is moving up or down the line ; and in all the Tables 

 given in this communication the letters " u " or " 6?," placed beside 

 the degrees of deflection, give the direction of the current in the above 

 popular terms. The galvanometer, with its appliances, accompanies 

 this communication, and is placed on the table as in situ, and will 

 at a glance give an idea of the arrangement, of which also the author 

 gives a plan. 



A Table is given of earth-currents collected at Tonbridge, in Oc- 

 tober 1861, on the lines in question, together with the Meteorolo- 

 gical Register of the month. An analysis of these observations follows, 

 included with which is an analysis of all observations of a like cha- 

 racter that were made in the subsequent month of November. 



A few cases are recorded in which the earth gave no sign of cur- 

 rent. No stress is laid on this, because a closer investigation with 

 more delicate instruments might have given positive results. 



The contents of the Table are divided into Normal, Abnormal, 

 and Exceptional. Out of a total of 276 observations, 230 gave nor- 

 mal results, confirming the conclusion already arrived at, that the 

 prevailing direction of earth-currents was approximately N.E. or S.W. 

 Whether one or other of these directions prevailed more or less at 

 different periods of the day did not appear, the observations not 

 being sufficiently consecutive. Father Secchi's views of the relation 

 between metereological phenomena and magnetic variation are re- 

 ferred to. The author has reason to conceive that sunshine or cloud, 

 heat or cold, influence the relative values of the current collected 

 from different parts of the same district ; in connexion with which 

 he refers to a group of night observations, which form part of the 

 series made in October, and also to the want of consistency in the 

 relation between two derived currents collected at the same time from 

 different parts of the same plane. He gives a few extracts from the 

 Table, showing how very variable are the relations ; for instance, 

 15 : 15 ; 15 : 30 ; 15 : 35 ; 13 : 38 ; 18 : 21 ; and so on. 



Professor Loomis's " Eighth Article " on the subject is referred to ; 

 and the correspondence between the results at which he arrives by 

 other processes, and those to which Mr. Walker arrives by the me- 

 thods herein described, are given. 



