8 Mr, C. Paeke on the Scales of the 



so, but always speaks of the length and resistance of the wire. 

 So that I do not consider the publication of my experiments to 

 be superfluous. 



I have, moreover, repeated the observations in the manner 

 described by Koosen, and found them confirmed in the main 

 point, as was to be expected j yet I have also observed that it 

 depends on the relation between the length of wire in the accessory 

 coil and in the inductorium. An accessory coil of 10,000 feet 

 took away completely the sparks of an inductorium of 23,000 

 feet, while it left untouched those of a small instrument of 3000 

 feet. The phenomenon is best seen as one of partial currents and 

 of resistance when a hemp thread 5 or 6 feet in length, moist- 

 ened with spring-water, which is fixed insulated in the air, once 

 backwards and forwards, and connected with the poles of the 

 spark micrometer. By moving a wire bridge laid across, it can 

 be shortened at pleasure for the current, and it may be observed 

 that the first action upon the sparks consists in an attenuation 

 of them. 



II. On the Discrepance between the English and French Baro- 

 meter-Scales; and on the Corrections necessary in reducing the 

 Readings to the Freezing-point. By Charles Packe, Esq. 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



AVING brought out with me a barometer graduated with 

 a double scale, reading millimetres on one side and inches 

 on the other, I have been at some pains to investigate the slight 

 apparent anomaly existing between the French and English 

 scales as compared with the boiling-point, which I think may- 

 be satisfactorily accounted for in the following manner : — 



Boiling- Barometer, 



point. , in. mm. -> r in. mm. 



212° F., J 29-905 or 759-58, I ' 29'922 or 760, 



or = j as given by the Kew <—\ as given by Regnault in 

 100 C. Committee of the British his Tables of the Elasti- 



Association. J *- city of Vapour. 



The larger portion of this discrepance arises from the differ- 

 ence of the standard temperature of the scales of the English 

 and French barometers ; the remainder is accounted for by the 

 difference of latitude producing a variation of gravity. 



First as to the discrepance arising from the standard tempe- 

 ratures. That of the English barometer being 30° F. higher 

 than that of the French scale, when the mercurial column is re- 



