MODr:S OF EQUALIZING ARCS OF VIBRATION. J^ 1 



As this last mixture is capable of attracting in some degree 

 the liurnidlty of the air, I should rather think, that the cot- 

 ton treated with the Hist is more liable to take fire*. 



The experiments 1 have continued to make on the use of ^" sallinc: per 



galls, in the manufdf ture of Adrianople red, lead me to be- alumuie fonn- 

 lieve, that the alumine is fixed in the cotton in consequence <^'^h and after 

 of the formation of a gallate of alumine, from which the ^Vjg ^i]^^^^^ 

 gaUic acid is afterward attracted by an alkaline carbonate 

 previous to the dyeing. As soon as I have satisfied myself 

 of tlie truth of this supposition, I will not fail to publisli an 

 account of my experiments. 



VIJ. 



Account of Inventions Jbr equalizing the long and fiort Arcs 

 of Vibration in Timekeepers ; 6^ Mr. Wilham Hardy, 

 No. 29, Coldbaih Squaref. 



' Jl HE equalization of the time of different arcs of vibra- Equalization 

 tion of the bain nee of a time keeper havinor lately ffiven rise ^^ ^^^'^ "^ ^'' 



11- • T 1 r,-> p 1 * bratl.n effect- 



to much discussion, I beg leave to ofierfor the approbation ed three ways. 



of the Society three different modes of obtaining- this end. 



The first method is by a straight spring placed edgewise ist method. 



acrossthediameter of the impellent pallet a. Pi. I!, fig. 2 and 



3, and screwed at the end opposite to the direction of the / 



wheel, on its approach toward the centre of this pallet ; at 



the other extremity of this spring is a flat face, or curved 



surface, to receive the approaching tooth of the escape 



wheel, which gives the impulse; this spring acts between 



two pins placed in the pallet near its end. By reducing 



this spring to a certain degree of strength, so that it may 



yield a little to the force of the wheel in giving the impulse, 



the different vibrations will be performed in the same time; 



but the proper degree of strength can only be determined by 



repeated trials. This method possesses besides this farther Advantage. 



advantage, that the acting surfaces are not so liable to be in- 



* Perhaps not, for this very reason. T. 



+ Transact, of the Society of Arts, vol, XXV, p. 113. The silver 

 medal of the Society was voted to Mr. Hardy for this invention. 



E 2 jured 



