SKETCH OF WILLIAM CRANGH BOND. 407 



sions of the star Vega. We have reason to believe this to be the 

 first successful experiment ever made either in this country or 

 abroad." Some daguerreotypes of the moon and certain stars 

 were exhibited in the World's Fair of the following year at Lon- 

 don, and received a council medal. 



The inventive skill which won success for Bond as an artisan 

 appears in certain astronomical appliances and methods devised 

 by him. The great telescope is poised thirteen feet above the 

 floor of the observatory's dome. It has a vertical sweep of more 

 than ninety degrees, and can, of course, make a complete revolution 

 about its axis of support. An observer would evidently have to 

 be something of an acrobat to use it successfully, unless a suitable 

 chair could be obtained. There was none in the world that filled 

 all the requirements, so Prof. Bond invented and made one. It is 

 in use unchanged to this day, and by means of its ingeniously 

 combined wheels, cogs, and pulleys the observer can quickly and 

 easily place himself anywhere along the vertical quarter-circle 

 and horizontal full-circle traversed by the eyepiece of the tele- 

 scope. 



Certain experiments for determining differences of longitude 

 by the aid of the telegraph were undertaken by the Coast Survey 

 in 1848, Prof. Bond being one of the special assistants whose serv- 

 ices were secured for this work. While engaged in these experi- 

 ments the idea occurred to him, as it had to one or more others, of 

 using an automatic circuit interrupter in place of human nerves 

 and muscles as the connecting link between the astronomical clock 

 and the electric wire. Fear of injuring the clock had prevented 

 the use of such a device, but Prof. Bond obtained authority to 

 have a clock made especially for this work, at the expense of the 

 survey. This was done, and the device was found to operate per- 

 fectly and without injury to the clock. "But another and far 

 more serious difficulty presented itself," says Prof. Bond, referring 

 to this matter in one of his reports, " in the accurate registry of 

 the beats of the clock after being transmitted by the galvanic cir- 

 cuit; and it was at this point that further progress in the appli- 

 cation of this method to astronomical observing was arrested." 

 Attempts to overcome this difficulty were made by various in- 

 ventors in the course of the next two years, but nothing satisfac- 

 tory came of it before April 12, 1850, when Bond submitted to the 

 Coast Survey an apparatus invented by him and his sons George 

 P. and Richard F. Bond. It was named at first, from one of its 

 peculiar parts, the " spring governor," but the more comprehen- 

 sive title of " chronograph " was applied to it later. The appara- 

 tus was at once adopted for use by the survey. It was taken by 

 Mr. G. P. Bond on his tour to Europe of the next year and exhib- 

 ited before the Royal Astronomical Society of England and the 



