280 



ELECTRICITY. 



to exchange signals between the two, the elec- 

 tric current passing over the interval. Mr. 

 Loomis conceives the bold idea of applying 

 this principle to international telegraphy. He 

 would build a high tower on the loftiest peak 

 of the Rocky Mountains, and on that erect a 

 flag-staif, put up a similar construction on one 

 of the highest peaks of the Alps, attach his 

 electric apparatus to each, and is hopeful of 

 transmitting messages by sufficiently strong 

 currents, between those points, through the 

 theoretically favorable medium of the upper 

 air. In the bill, as passed, there is a clause 

 which seems to give the company a right to 

 use any existing means of telegraphic inter- 

 course, so that if the aerial telegraph should 

 not be practically successful, the company 

 could fall back on the common system of wires 

 and poles. In order to introduce the telegraph 

 into the different States, the company must ob- 

 tain permission from the Legislatures thereof. 



The Allegheny System of Time-Signals. 

 Mr. P. O. Langley fully describes this in the 

 American Journal of Science. The plan was 

 worked out for the managers of the Pennsyl- 

 vania Central Railroa'd, in 1869, and has since 

 furnished to that line its standard time, ajid 

 also supplies time to Philadelphia and the 

 East, as far as Lake Erie on the north, and 

 Chicago on the west, besides* regulating the 

 clocks on a number of minor roads, over 

 whose wires it goes, as well as those of the 

 principal Southern lines connecting the Atlan- 

 tic with the Mississippi, thus passing over sev- 

 eral thousand miles daily. The observatory 

 is on the summit of the ascent on the northern 

 side of the valley of the Ohio, about two miles 

 in a direct line from the offices of the Western 

 Union Telegraph Company in Pittsburg. Ob- 

 servations for time are taken every fine night 

 of the year, except on Sunday, from three to 

 six stars, and the corrections made, if needed. 

 Distant clocks are not controlled sympatheti- 

 cally (on a well-known plan) by the observa- 

 tory clock, but only have the time furnished 

 to them, so that they may be regulated twice 

 a day. Mr. Langley concludes his paper as 

 follows : 



The necessity of a uniform standard of time over 

 tlie whole country, which was alluded to in the outset 

 as one of growing importance, has not been further 

 directly touched upon in this article, which is yet, as 

 a whole, devoted to describing the means of meeting 

 it. The evident tendency, in thus sending the time 

 from one standard over so large an extent of terri- 

 tory, is to diminish the number of local times, and 

 so prepare the way for a future system, in which, at 

 bast between the Atlantic and the Mississippi, they 

 shall disappear altogether. 



A step in this direction has been contemplated by 

 the managers of the roads uniting New York, Phila- 

 delphia, Pittsburg, and Chicago, who have intended 

 to use the time of the meridian of Pittsburg be- 

 tween the two extreme point? mentioned, running 

 all trains from New York to Chicago by this time 

 alone, in place of using successively the local times 

 of Philadelphia, Altoona. and Columbus, as at pres- 

 ent. Such a change would have already taken place 

 during the last summer, except for an unexpected 

 cause of delay, on whose removal it will be effected. 



The labors of this and of other American observa- 

 tories are tending to the same important end, that 

 of the ultimate adoption of some single time for all 

 the country east of the Mississippi, by which not 

 only the railroads, but cities and the public gener- 

 ally, will regulate themselves. What point shall be 

 chosen is of less importance than that some one shall 

 be used, and universally. 



The subject is one which has hitherto attracted 

 little public attention, but it does not seem unsafe to 

 make the assertion that the causes which have 

 almost insensibly effected such a revolution in Eng- 

 land, will, in a few years more, bring it about here. 



Improved Electric Clocks. Sir Chas. Wheat- 

 stone, by substituting magneto-electric cur- 

 rents obtained from permanent magnets, for 

 the voltaic battery, has removed some of the 

 imperfections and inconveniences pertaining 

 to the old style of electric clocks. His system 

 consists of two parts: the going clock, from 

 which the magnetic currents are obtained, 

 which is driven by a weight ; and the sympa- 

 thetic clocks, deriving their motion from the 

 currents obtained from the going clock. Each 

 of the sympathetic clocks is provided with an 

 ordinary galvanometer coil and magnetized 

 needles the latter being attached to, an axis 

 having a pinion which gears into a crown- 

 wheel. This wheel in turn gears into a train 

 of wheels to which the clock-hands are at- 

 tached. The action is then as follows : Sup- 

 pose the needles to be parallel to the coils at 

 starting, and the pendulum to be at one limit 

 of its distance of oscillation, the pendulum, in 

 swinging, to its other limit, sends a current 

 through the coil, and causes the needles of 

 each of the clocks in circuit to be deflected ; 

 and, as the needles can move with very little 

 friction with their axes, they are carried 

 round, by their momentum, half a revolution 

 or more. On the pendulum, now swinging the 

 other way, a current is sent in the reverse 

 direction, which, as the position of the poles 

 of the needles with respect to the coils is now 

 reversed, sends the needles round again an- 

 other half-revolution in the same direction, so 

 that, for each complete oscillation of the pen- 

 dulum (backward and forward), the needles 

 make one complete revolution, and thus a con- 

 tinual rotatory motion of the needles, and 

 consequently of the hands of the clock, is kept 

 up. It might be thought, perhaps, that some 

 special contrivance would be necessary, in 

 order that the needles should be only able to 

 move just half a revolution for each current, 

 lest the succeeding current should either not 

 be able to give them a full impulse, or would 

 have the effect of simply making them oscil- 

 late backward and forward without imparting 

 a rotatory motion to them ; such a contrivance, 

 however, is not necessary, for it is found that 

 when the clocks are started, after a few revo- 

 lutions the rotatory motion of the needles 

 becomes perfectly uniform, and continues so as 

 long as the going clock works. The going 

 clocks are provided with an arrangement by 

 which any slight errors in their rate of going 

 can, if necessary, be corrected by a standard 



