J^^ MODE OF CONVEYING INTELLIGENCE, 



sensibility and the range of the instrument may be infinitely increased ; 



insuuroeut^ for, on the one hand, by enlarging the proportion betweeu 

 the diameters of the wide and narrow part3 of the tube, we 

 enlarge in a much higher proportion the exteat of scale 

 corresponding to any given variation of velocity : and on the 

 other hand, by deepening the cup so as to admit when it 

 is at rest a greater height of meicui^ above the lower end 

 of the tube, we lengthen the column of spirits which the 

 mercury can support, and consequently enlarge the velo- 

 city, which, with any given sensibility of the instrument, is 

 requisite to depress the spirits to the bottom of the scale. 



Applicable to Hence the tachometer is capable of being employed in very 



riments.^''^^" <le''<"»t'^ philosophical experinvents, more especially as a scale 

 might be applied to it, indicating equal increments of ve- 

 locity. But in the present account it is merely intended to 

 state how it may be adapted to detect in machinery every 

 deviation from the most advantageous movement. 



vir. 



A Mode of conveying Intelligence from a reconnoitring 

 Party. In a Letter from a Correspondent, 



To W. NICHOLSON, Esq. 

 SIR, 



Mode of con- J[ Herewith send you u model, which I denominate a Hip- 



gtnce by a re- pograpli, and which appears to me likely to be of use in the 



connoitring march of troops, &c. 



^*' ^' It may consist of any number of men and officers, but I 



conceive an officer and six men quite sufficient. The use it 

 seems most adapted to is, when a mountain or high ground 

 is in front, and it is wished by the commanding officer to 

 know what may be on the other side, by dispatchiflg such a 

 number of men intelligence ctm be at once conveyed by 

 changing the front of one or more men to express numbers, 

 or permanent signals, as agreed on, as the boards of a tele- 

 graph ; and by ihe officer placing himself on either flank, 

 centre, or rear, the numbers would be quadrupled. I know 



by 



