178 THE POPULAR SCIENCE MONTHLY. 



could be remedied by a board of inspection appointed by the insurance 

 companies, which should refuse to insure the cargo or hull of any sea- 

 going ship unless her chronometers were found, after trial, to be satis- 

 factory. Part of the error is undoubtedly due to the bad navigation 

 of the captain, who, in distant ports not provided with time from an 

 astronomical observatory, determined the error of his chronometer 

 himself, and that not always correctly. But the great source of error 

 was the fact that the rate of the chronometer assigned at the port of 

 sailing did not serve throughout the voyage. 



It will be then of some interest to describe the measures now tak- 

 ing in the United States to provide the sea-going ships sailing from 

 our various ports with an accurate standard time; and, further, to ex- 

 plain the facilities offered by the United States Naval Observatory to 

 railways, manufactories, and others, in the providing of a time by 

 which to reo;ulate their affairs. 



The Superintendent of the Naval Observatory, the late Rear-Ad- 

 miral C. H. Davis, some time ago proposed to the authorities of the 

 Western Union Telegraph Company the erection of a large time-ball 

 upon their new building on Broadway, near the City Hall. This 

 time-ball it was proposed to drop daily by telegraph at New York 

 noon. It is to be dropped exactly at 11'' 47" 49.53' a. m. of Washing- 

 ton local time, which is New York noon, 12'' 0" 0.00^ or 4'' 56" 1.65' 

 of Greenwich time. It will thus be available both for the citizens, 

 railways, etc., of New York, and for the ships sailing from port It 

 is to be mounted upon the large iron flagstaff on top of the east tower 

 of the Western Union building, the base of the staff being about 230 

 feet above the street, and the ball being dropped from a part of the 

 staff about 25 feet above this. The whole expense of the apparatus, 

 which is considerable, and the management of it, which requires the 

 attention of a laborer and of a skilled electrician, have been assumed in 

 a public-spirited manner by the Western Union Telegraph Company, 

 for the benefit of the citizens and the shipping of New York City. 



The apparatus employed may be briefly described as follows : 



Around the iron mast, which is of great strength, is fastened an 

 iron jacket, sliding up and down freely iipon it. On this is fitted a 

 ball three feet six inches in diameter, made of copper-wire netting, and 

 painted black. The interstices of the netting allow of a free passage 

 of the wind through the ball, so that less strain is exerted upon the 

 mast,and a larger ball is permissible than there otherwise would be. 



At the bottom of the jacket are a coiled spring and a buffer en- 

 circling the mast, which take the considerable blow of the falling 

 ball. At 11" 55" of New York time, the ball is hoisted half-way or 

 more up the mast, and at 11'' 58" it is hoisted completely up, and the 

 halliards are attached at 11'' 59" to a lever actuated by an electro- 

 magnet. At exactly noon an electric signal releases the lever, and 

 the ball falls by its own weight. 



