158 YEAR-BOOK OF FACTS. 



passage of the extra current, was obtained. The brightness and 

 loudness of the spark were augmented when a core of soft iron was 

 placed within the coil. The disruption of the current took place 

 between the poles of an electro-magnet ; and when the latter was 

 excited, an extraordinary augmentation of the loudness of the spark 

 was noticed. 



An experiment was next shown for the purpose of illustrating the 

 important influence which the mode of breaking contact may have 

 upon the efficacy of an induction coil. 



The splendid effects obtained from the discharge of Ruhmkorff's 

 coil through exhausted tubes were next referred to. 



Aftera variety of other most beautiful experiments with a powerful 

 battery of 400 of Grove's cells, lent by Mr. Gassiot, the discharge of 

 the buttery was finally sent through a tube, whose platinum wires 

 were terminated by two small balls of carbon : a glow was first pro- 

 duced ; but on heating a portion of the tube containing a stick of 

 caustic potash, the positive ball sent out a luminous protrusion, 

 which subsequently detached itself from the ball ; the tube becoming 

 instantly afterwards filled with the most brilliant strata. "There 

 can be no doubt," said Dr. Tyndall on this point, " that the superior 

 effulgence of the bands obtained with this tube is due to the cha- 

 racter of its electrodes : the lands arc the transported matter of these 

 electrodes. May not this be the case with other electrodes ? There 

 appears to be no uniform flow in nature ; we cannot get either air or 

 water through an orifice in a uniform stream ; the friction against the 

 orifice is overcome by starts, and the jet issues in pulsations. Let a 

 lighted candle be quickly passed through the air, the flame will break 

 itself into a beaded line in virtue of a similar intermittent action ; 

 and it may be made to sing, so regular are the pulses produced by 

 its passage. Analogy might lead us to suppose that the electricity 

 overcomes the resistance at the surface of its electrode in a similar 

 manner, escaping from it in tremors ; the matter which it carries 

 along with it being broken up into strata, as a liquid vein is broken 

 into drops." 



THE ATLANTIC CABLE. 



A Retort on the state of the Atlantic Cable in Trinity Bay, dated 

 St. John's (N.F.), July 3, 1S00, has been received. It states : — 



" Al: i irm | its to raise the cable by grapnelling, in order to 



i condition, and >.% i 1 1 1 ■ riew to land it, weregrel f > . og to report that, 

 although we have on many occasions been able to raise the bight, and so get nu 

 board at different timi cable, in all amounting to about seven miles, 



ire have invariably found I I miles off. then de- 



tails thi from the L2th to t be 80th June, on 



was hooked at least th ad probably more during the day, but broke 



before reaobingthe surface. \t la t s li^ht can il 



i for about :t" yards ; the outer end »>i^ found to be broken 

 about 200 yards off About two miles of the inner <'<»! were recovered, when it 

 parted again at s weak place where there was nothing but the gutta i crohai overed 

 wire left: this,howi • bring the eable to the surface, when it 



snapped ild be secured bj a stopper. The point where we last ^rnp- 



n.lli-.l tliU day was ■ ! >t unejoining field* Point and Copper 



I land, in 140 fathoms t^ater. Although mud is shown on I r<- aro 



must unquestionably nx-Us also, iia wub too plainly mdioated by the ntuto of tho 



