D. CHEMISTRY AND METALLURGY. 101 



of volume accompanying solution, and has arrived at the fol- 

 lowing: general conclusions: 



1. In every case there is a diminution in volume when an 

 anhydrous salt is dissolved in water that is, the volume of 

 the solution is less than the sum of the volume of the water 

 and salfc. Of all salts tried, ammonium chloride gives the 

 least contraction. 



2. The first portions of the anhydrous salt correspond to 

 the maximum of contraction. As the strength of the solu- 

 tion increases, the contraction diminishes, until, with very sol- 

 uble salts, when the solution is nearly saturated, the contrac- 

 tion is almost insensible. 



3. Viewed with regard to their energy of contraction, the 

 substances experimented on may be ranged in the following 

 order, beginning with the greatest contraction :.(.) With re- 

 spect to the non-metallic radicals carbonates, sulphates, chlo- 

 rides, nitrates, iodides ; (b.) With respect to the metals iron, 

 zinc, copper, magnesium, strontium, barium, calcium, sodium, 

 lead, potassium, ammonium. 



4. Hydrated salts give far less contraction than the corre- 

 sponding anhydrous salts; the contraction is smaller as the 

 number of- molecules of water of crystallization becomes 

 greater. 



5. Salts which crystallize in the anhydrous state are those 

 in which the co-efficient of contraction is smallest. 21 A, 

 March, 1872,217. 



mexsbrugghe's LAW IX PHYSICS. 



Professor Van der Mensbrugghe, of the University of Ghent, 

 has announced as a law in physics that each time a liquid of 

 strong superficial tension, and containing gas in solution, is 

 brought into contact with a liquid of feeble tension, there is 

 a more or less decided disengagement of the eras dissolved in 

 the liquid. 



The accuracy of this proposition the author proposes to es- 

 tablish hereafter in a special memoir, and announces it at 

 present simply to secure priority of presentation. One illus- 

 tration presented by him is to the effect that if a drop of al- 

 cohol or of ether be introduced into distilled water half filling 

 a small vial of one or one and a half inches in diameter, and 

 the liquid agitated, a lively effervescence will be observed 



