Relations between Electrical Measurements. 



523 



Table for the Conversion of British (foot-grain- second) System 

 to Metrical (metre-gramme-second) System. 





Number of 

 metrical units 

 contained in a 

 British unit. 



Log. 



Log. 



Number of 

 British units 

 contained in a 

 metrical unit. 



1. For M 



0-0647989 

 0-3047945 



00197504 



00060198 



0-461085 



0-140536 



00428346 



00359994 



2-8115678 

 1-4840071 



2-2955749 



3-7795820 

 T-6637804 

 11477874 

 2-6317949 

 2-5562953 



1 1884321 

 0-5159929 



1-7044250 



.2-2204179 

 0-3362196 

 0-8522125 

 13682051 

 1-4437046 



15-43235 

 3-280899 



50-6320 



166-1185 

 2-16880 

 711561 

 23-3456 



27*7782 



2. For L, * R, I, and V. 



1 r 



3. For F (also for foot- 1 



grains and metre- I 

 grammes) J 



4. For W 



5. For H and electro- ~! 

 chemical equivalents. J 



6. For Q, C, ande 



7. For E, m, q, and c ... 



8. For heat 





British System. — Relations between Absolute and other Units. 



One absolute fforce ~ AO , A /j^ weight of a grain ■ T , 

 ., - < i =0-0310666 £ f • & m London, 

 unit oi Lwork loot-grains 



In ("weight of a grain =32 . 1889 absolute units of force 

 .London ^one root-grain work. 



One absolute fforce 1 unit weight " 



unit of \work ~ ~ g unit weight x unit length ever y wheve ' 



g in British system = 32'088 (1 + 0*005 133 sin 2 X), where 

 X= the latitude of the place at which the observation is made. 



Heat. — The unit of heat is the quantity required to raise the 

 temperature of one grain of water at its maximum density 1° 

 Fahrenheit. 



Absolute mechanical equivalent of unit of heat =24861 = 772 

 foot-grains at Manchester. 



Thermal equivalent of an absolute unit of work = 0'000040224. 



Thermal equivalent of a foot-grain at Manchester = 0*0012953. 



Electrochemical equivalent of water = 0'02_, nearly. 



Metrical System. — Relation between Absolute and other Units. 



One absolute fforce A nQArkQ01 weight of a gramme , T) . 

 ., o < i =\)'\)W\)&Zl ° . D at rans. 



unit ot (jvork metre-gramme 



At fAeweightofagramme =9 . 80868abso]iiteunitsof force 



Pans \ or metre-gramme work. 



One absolute fforce — 1 unit weight 



unit of \ work "" g unit weight x unit length 



g in metrical system =9'78024(1 + 0-005133 sin 2 \), where 



\ = the latitude of the place where the experiment is made. 



Heat. — The unit of heat is the quantity required to raise one 



gramme of water at its maximum density 1° Centigrade. 



2M2 



everywhere. 



