Royal Astrofiomical Society. 461 



" Recently Prof. Bond and Dr. Locke have invented different pro- 

 cesses, which are described in Mr. Walker's Report. 



" Prof. Bond proposes to make circuit by the metallic contact of 

 insulated portions of the pallet and escapement-wheel. Dr. Locke, 

 like Mr. Wheatstone, uses a metallic wheel on the arbour of the 

 seconds' hand. This wheel has sixty teeth, each of which when 

 horizontal strikes against a platinum lever or tilt-hammer, weighing 

 two grains. The rising and falling of the hammer from a bed of pla- 

 tinum breaks and makes the galvanic circuit. The fulcrum of the tilt- 

 hammer and the platinum bed rest severally on a small block of wood. 



" The object of all these methods is to cause a delicate astrono- 

 mical clock to make and break the galvanic circuit every second, 

 without injury to the machinery or rate of the clock. The mode of 

 action of such alternations on Morse's electro-magnetic telegraph 

 register, as now in daily use in the United States, is the same for 

 each of these methods. 



" llie automatic clock register thus formed consists of a graduated 

 fillet of paper delivered pretty uniformly at the rate of an inch per 

 second. The beginnings of minutes, and fives and tens of minutes, 

 and of seconds, and fives and tens of seconds, are distinguished from 

 each other by the lengths of the corresponding imprinted blank spaces. 

 The printed second consists of an indented line of about nine-tenths 

 of a second or less, and of a blank space for the remainder. The rate 

 of the delivery of the paper is regulated by a centrifugal clock like 

 those of the Munich equatoreals. An error of two seconds per 

 minute in the rate of delivery causes only an average error of one- 

 hundredth of a second in the register of a date. 



" The printing of the date of any event not susceptible of auto- 

 matic register, but dependent for our knowledge of its occurrence 

 upon human sensations, is effected by tapping gently at this date on 

 a break circuit telegraph key, so as to insert in the line of the auto- 

 matic clock register a short blank space, whose beginning marks the 

 instant of the tap. Should this blank space occur near that of the 

 automatic clock register, the fact would identify its date. For iso- 

 lated events the finger dwells long enough on the key to be sure of 

 cutting off some portion of one of the indented lines. The dates 

 susceptible of impression with advantage on the automatic clock re- 

 gister are such as the phases of an eclipse or occultation, or the 

 bisections of a star or comet, or of a planet's centre or limb, by the 

 wires of a transit instrument. The association of the nerves and 

 sensations of sight and touch is known to be far more intimate than 

 that of those of the eye and ear. The art of tapping at the proper 

 dates requires far less practice and experience than that of counting 

 beats and estimating fractions of a second. The labour of counting 

 beats and of writing down the dates being here dispensed with, the 

 equatoreal intervals of the transit wires may be reduced to two 

 seconds of time, or even to less, and fifty bisections may now be 

 registered in the same time as seven are in the ordinary way. The 

 three advantages of Mr. Walker's method are respectively, — 

 - " 1st. The facility of acquirement of the practical skill for observing. 

 5 " 2nd, The twofold precision nearly of a single observation. 



