126 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



menclature of units of force and energy, under which head 

 the committee is itself prepared to offer certain definite recom- 

 mendations, which are as follows : First, the gramme, centi- 

 meter, and second are recommended as the units of mass, 

 length, and time, respectively ; a combination which has the 

 advantage of making the unit of mass appear identical with 

 the mass of the unit volume of water in other words, of 

 making the value of the density of water appear equal to 

 unity. From these fundamental units the units of electrical 

 and magnetic magnitudes, now in common use, may be de- 

 rived ; and it is recommended that, until special names shall 

 be prepared for them, they be distinguished from absolute 

 units, otherwise derived, by the three initial letters C. G. S. 

 As regards the name to be given to the C. G. S. unit of force, 

 it is recommended that it be a derivative of the Greek word 

 Swapic the form dynamy appears to be the most satisfac- 

 tory to etomologists. The work done by this force working 

 through a centimeter is the C. G. S. unit of work, for which 

 is proposed a name derived from the Greek, erg ; the C. G. S. 

 unit of power is the power of doing work at the rate of one 

 erg per second, and the power of an engine can be specified 

 in ergs per second. The common and extremely variable 

 unit of one horse-power is about three fourths of an erg-ten 

 second. For the expression of high decimal multiples and 

 sub-multiples, the system introduced by Mr. Stoney is recom- 

 mended. It consists in denoting the exponent of the power 

 of ten, w T hich serves as a multiplier by an appended cardinal 

 number, if the exponent be positive, and by a prefixed ordi- 

 nal number when the exponent is negative ; thus ten to the 

 ninth power, or one thousand million grammes, constitutes a 

 "gramme-nine," and the one thousand millionth of a gramme 

 constitutes a "ninth-gramme." Proc. British Association. 



NEW INSTRUMENTS EXHIBITED AT THE APRIL SOIREE OE THE 



ROYAL SOCIETY. 



At a recent soiree of the Eoyal Society (being the first 

 held in its new apartments) there was a remarkably good 

 display of scientific apparatus, including the following pieces 

 in the department of physics, some of which may possibly be 

 new 7 to American readers. Mr. Crookes exhibited his experi- 

 ments showing the attraction and repulsion accompanying 



