616 REPOET— 1888. 



La comparaison de cette derniere image arec I'image normale conduira a 

 reconnaitre et a mesurer le temps 6coule pendant la production successive des 

 diverses parties de I'^tincelle. 



On n'a ex6cut(5 encore que quelques experiences. Elles ont 6t6 faites sur des 

 6tincelles produites avec une bobine de Rhumkorfl'; et d6ja on a pu constater que 

 dans la production des dtincelles a plusieurs branches partant d'un meme pole la 

 production des diverses branches n'est pas simultan^e niais successive. 



Pour une meme etincelle meme la manifestation du phenomene lumineux donne 

 lieu a des circonstances singulieres sur lesquelles nous aurons a revenir. 



Ces experiences seront poursuivies. Elles seront appliqu^es notaniment a 

 retude des phenomenes de la foudre. 



Report of the Committee for constructing and issuing Practical Standards 

 for use in Electrical Measurements. — See Reports, p. 55. 



5. On Standards of Electrical Resistance. By R. T. Glazebkook, F.R.S. 



6. On the C.G.S. Units of Measurement. Bij W. H. Preece, F.R.S. 



It is suggested that the unit of work equivalent to 10^ ergs be called the Joule, 

 as proposed by Sir William Siemens. We should then have these relations : — 



One joule = 10'' ergs = '1^4 calorie (gramme-water degree). 



One watt = one joule per second = "24 calorie per second. 



One calorie = 4-2 joules = 42000000 ergs. 



One British thermal unit (pound-water degree Fahr.) = lC58 joules = 252 

 calories. 



The inconvenience of making the volt 10^ units instead of 10^ C.G.S. units, the 

 very rough approximation of the legal ohm, and the necessity for some unit mag- 

 netic field are considered, and it is recommended that the standard of pure copper 

 should be redetermined, for Matthiessen's standard is known to be wrong. 



7. Electrometric Determination of ' v.' 

 By Professors Sir W. Thomson, F.R.S., Ayrton, F.R.S., and Perrv, F.R.S. 



WEDNESDAY, SEPTEMBER 12. 



The following Reports and Papers were read : — 



Report of the Comonittee for considering the desirahility of introducing a 

 Uniform Nomenclature for the Fundamental Units of Mechanics. — See 

 Reports, p. 27. 



2. Second Report on our Experimental Knowledge of the Properties of 

 Matter. By P. T. Main, if.^.— See Reports, p. 465. 



3. On the Mechanical Arrangements of the Analytical Engine of the late 

 Charles Babbage, F.R.S. By Major-General H. P. Babbage. 



The object of this paper is to give some idea of the mechanical contrivances 

 employed to govern and control the analytical engine of Charles Babbage. It is 

 scarcely possible to give in a short space a full abstract of what is already very 

 condensed. Those who desire further information are referred to a volume of 



