316 Registering the Variations of the Tide and Wind. 



the machine, under what appellation the wind that blew at any 

 particular period may be classed, together with the point of the 

 compass from which it blew. Thus, for instance, supposing the 

 wind dial-face, represented in Fig. 5, to have been applied on the 

 1st day of a particular month, we find that during the 1st, 

 2d, and until midday of the 3d, the wind gradually veered from 

 N. to N.E. by E., when it commenced a strong breeze, which 

 continued till about six o'clock in the evening of the 7th. The 

 wind then rapidly turned to the N., from which quarter it blew 

 furiously until about six o'clock p. m. of the 10th. It then sub- 

 sided, and gradually veered by the W. to the S. and S.E., and 

 about midnight on the 14th, blew hard from the S., and so con- 

 tinued till midday on the 16th, and so on. Thus, the direction 

 of the wind, at any particuliar period, would be indicated with 

 precision, and it is expected that the appearances on the face 

 would enable us, after having experienced the action of the ma- 

 chine, to form a tolerably correct idea of the simultaneous state 

 of the wind. 



In the constraction of the machine, various particulars must 

 be well attended to. For instance, the float will require to act 

 upon a surface of water undisturbed by the waves of the sea, to 

 secure which, the space for the float''s action should be enclosed, 

 tlie water having ingress and egress through a small aperture ; 

 the aperture will be amply large, if its area be one square" inch 

 for each superficial foot of water surface that the enclosed space 

 contains. The dial-faces may be formed of thick white paper, 

 made for the purpose, and kept with the required figures and 

 divisions of the circle ready printed upon them fit for use. A 

 fresh face may be placed upon each dial plate once per month, 

 or at such other regular periods as from experience may be found 

 more convenient. The date should always be marked upon a 

 new face upon its being fixed to the dial-plate, and the old faces 

 carefully preserved. On the tide dial-faces, midday is denoted 

 by the letter M, to distinguish it from midnight. 



The small tubes which contain the markers, ai-e so contrived, 

 that a small slip of pi'epared black lead is forced with a gentle 

 pressure against the face of the dial, by a slight wire spiral 

 spring enclosed in the tube, whereby a constant point is kept 

 up. Experience of the practical operation of the machine, 



