66 H. F. Blanford — Van RysselbergTie Meteorograph. [ApeiL, 



most effective of all, is the very beautiful instrument, originally designed 

 by M. Van Kysselberghe and constructed with many original improve- 

 ments by the very ingenious mechanician M. Schubert of Ghent. 



Two of these instruments have lately been received for use at Allaha- 

 bad and Lahore ; and while awaiting the provision of the requisite accom- 

 modation, at the places of their destination, one of them has been set 

 up and is now in operation at the Meteorological office, No. 4 Middleton 

 ltow, Calcutta, and is open to the inspection of such members of the Society 

 as may desire to examine it. 



The details of the mechanism could hardly be understood without 

 watching the instrument at work, and even then not without some careful 

 study and examination. All that could be attempted would be to give 

 some general idea of its principles. 



The instrument registers, at successive intervals of ten minutes, the 

 readings of (1), the dry and wet bulb thermometers ; (2), the rain gauge ; 

 (3), the direction of the wind; (4), the height of the barometer and (5), the 

 rate of the wind movement in the previous interval. All these are engraved 

 in succession on a thin metallic plate fixed on a revolving cylinder, and, 

 at the same time, the scale of all the instruments is engraved, so that the 

 values may be at once read off ; and when the plate is removed from the 

 cylinder and the trace bitten in with etching liquor, it may be printed 

 from in an ordinary copper-plate press, and any required number of copies 

 obtained for distribution. 



The principal motive power by which the recording cylinder is 

 made to revolve, and the electric connections with the several instru- 

 ments made and interrupted in succession, is given by clockwork. 



This is set in action, on the completion of each ten minutes interval, 

 by an ordinary clock, the minute-hand of which makes contact with a spring 

 projecting from the brass rim which surrounds the clock face, and com- 

 pletes an electric circuit ; the current of which, acting on an electro-magnet 

 releases a detent, allowing the cylinder to revolve, and at the same time 

 causing a shaft to set in action a somewhat complex system of commutators. 



Two batteries are employed, each consisting of eight Daniell's 

 elements. One of these serves to work the burin which engraves the 

 trace, by acting on an electro-magnet which pulls back the burin from 

 the cylinder, against which it otherwise presses by means of a spring ; 

 the other, the regulating current, is directed through the several 

 instruments in succession by means of the commutators, and then, act- 

 ing on a series of electro-magnets makes and breaks the engraving 

 current at the proper intervals according to the values indicated by 

 the several instruments. The graduation is effected by passing one 

 or the other current through a brass ring which revolves with the 



