386 



Intelligence and Miscellaneous Articles. 



to what is thought by many physicists. This I arrived at in rny 

 memoir of 1877, for pressures below 40 atmospheres {Ann. de Chim. 

 et de Phys.), and which long before had been found by Colladon and 

 Sturm in their classical work Sur la Compressibilite des Liquides. 



I shall only give here the results of two series, one on water and 

 the other on ether. 



Water at 17° '6. 



■*■ 





Ether at 17°'4. 



Pressures, in 



Coefficients of 



Pressures, in 



Coefficients of 



atmospheres. 



compressibility. 





atmospheres. 



compressibility. 



atm. atra. 







atm. atm. 





Between 1 and 262 



0-0000429 Between 1 and 154 



0000156 



„ 262 „ 805 



00000379 



»» 



154 „ 487 



0000107 



„ 805 „ 1334 



0-0000332 



>> 



487 „ 870 



0-000083 



„ 1334 „ 1784 



0-0000302 



y> 



870 „ 1243 



0-000063 



„ 1784 „ 2202 



0-0000276 



„ 



1243 „ 1623 



0-000057 



„ 2202 „ 2590 



0-0000257 



„ 



1623 „ 2002 



0-000045 



„ 2590 „ 2981 



0-0000238 









At 3000 atmospheres the volume of water is reduced by one tenth, 

 and its coefficient of compressibility by one half. 



The study of ether will be resumed and carried as far as 3000 

 atmospheres. — Comptes Bendus, August 25, 1886. 



ON THE SPECIFIC INDUCTION CONSTANTS OF MAGNETS IN MAG- 

 NETIC FIELDS OF DIFFEEENT STRENGTHS. BY HILMAR SACK. 



Lamont concluded from his experiments on the changes effected 

 by the earth's magnetism on the magnetism of steel bars that the 

 change is greater when the force acts in opposition to the pre- 

 vious magnetization than when it strengthens it. Kohlrausch has 

 recently shown (Wiedemann's Anncden, vol. xxii. p. 415, 1884) 

 that such a difference does not exist, at any rate not for a field of 

 the strength of the earth's magnetism. 



The object of the present investigation is to ascertain within 

 what limits this equality of the specific induction constants holds. 

 The investigation in question was made at the invitation and under 

 the direction of Prof. Kohlrausch in the Physical Laboratory at 

 Wiirzburg. 



After describing in detail the method of the investigation and 

 the data obtained, the author summarizes the results in the 

 following terms : — 



As respects hardened and powerfully magnetized steel bars, — 



1. The coefficients of strengthening and of enfeeblement as 

 found by F. Kohlrausch were appreciably the same for fields of the 

 same strength as the horizontal component of the earth's magne- 

 tism, that is 0-2. 



