Intelligence and Miscellaneous Articles. 399 



Melting-point. 



Gallium no. 1 +30*14 



„ no. 2 . . +30-16 



„ no. 3 +30-11 



„ no. 4 +30-15 



no. 5 +30-18 



„ no.6. ...... +30-16 



Mean +30-15 



The specimen no. 4 was next placed for two hours in boiling 

 water ; and the innumerable globules formed were united by com- 

 pression. The melting-point had not varied at all. The metal was 

 therefore certainly free from potassium. 



The six specimens having been mixed, a fragment weighing 2| 

 centigrammes was taken and kept during half an hour in nitric acid 

 diluted with its volume of water, at a temperature of 60-70°. The 

 loss amounted to only a fraction of a milligramme. The melting- 

 point had remained fixed; for the metal fused very slowly at 

 + 30°-16, and crystallized very slowly at +30°-06. 



I shall shortly have the honour of submitting to the Academy 

 the new process which has served for preparing this gallium, of 

 which the constant melting-point denotes the very satisfactory purity. 



In May 1876 I essayed to measure the density of the gallium, 

 upon a specimen weighing 6 centigrammes ; I obtained 4-7 at 15° 

 (and relative to water at 15°). The mean of the densities of alu- 

 minium and indium being 4*8 (to 5-1), the specific gravity provi- 

 sionally found for gallium appeared to accord very well with a 

 theory placing this metal between indium and aluminium. Never- 

 theless the calculations instituted by M. Mendeleef for a hypothetic 

 substance which seems to correspond to gallium, at least as to 

 several of its properties, conducted to the number 5*9. 



Gallium crystallized under water decrepitates sometimes when it 

 is heated. Perhaps my first metal contained vacuoles filled with 

 air or water. I do not know if this cause of error was or was not 

 associated with others to falsify my first determination • if so, how- 

 ever, I avoided it afterwards by strongly heating the metal, and 

 solidifying it in a dry atmosphere. I then obtained higher densities 

 — varying, however, from 5*5 to 6'2, while the weight of the por- 

 tions taken did not exceed a few centigrammes. 



Lastly, I have just operated with e>8 centigrammes of gallium 

 obtained by combining the six specimens above mentioned. 

 Density at +23° (and relative to water at +23°). 



1st experiment 5-90 



2nd „ 5*97 



Mean 5*935 



The same gallium was afterwards kept during half an hour be- 

 tween 60° and 70° in nitric acid diluted with its volume of water, 

 washed, pretty strongly heated, and, finally, solidified in dry air. 

 Density at +24°-45 (and relative to water at +24°-45) =5-956. 



