Intelligence and Miscellaneous Articles. 79 



ON SUBOXIDE OF LEAD AND PROTOXIDE OF TIN. BY M. BOUS- 



S1NOAULT. 



By subjecting oxalate of lead to dry distillation, M. Dulong ob- 

 tained a black powdery residue, which he considered as lead of a low 

 degree of oxidation. M. Berzelius is of opinion that this new oxide 

 is produced when metallic lead is exposed to the atmosphere. The 

 existence of this suboxide is not, however, admitted by all chemists, 

 and its composition has not been determined. 



To determine the question M. Boussingault prepared suboxide of 

 lead, by decomposing the oxalate in a small glass retort. To obtain 

 it pure the body of the retort must be kept at a low red heat j at a 

 higher temperature some globules of lead are produced, and the glass 

 is attacked. 



When the disengagement of gas has ceased, the retort must be al- 

 lowed to cool without access of air. This is easily managed by adapt- 

 ing a long tube to the retort and plunging it into mercury. 



The suboxide of lead is of a very dark gray colour, almost black. 

 When heated below the fusing point of lead, it is converted into 

 oxide. Sulphuric, muriatic, and acetic acids attack it, especially when 

 heated ; oxide of lead is formed, which combines with the acids, and 

 metallic lead separates. 



When mixed with water and exposed to the air, the suboxide is 

 quickly converted into carbonate of lead ; under water, and without 

 the contact of the air, it suffers no change. Mercury rubbed with the 

 suboxide under water does not dissolve lead. This experiment seems 

 to prove that suboxide is not, as has been supposed, a mere mixture 

 of lead and oxide. 



In order to determine the composition of this suboxide it was con- 

 verted into oxide, and the absorption of oxygen noted : this was ef- 

 fected by heating it in a cupel to nearly a red heat. In two experiments 

 100 parts of suboxide became 103*6 of oxide, containing 7*2 of oxygen; 

 and as the oxygen which combined with the suboxide during calci- 

 nation amounted to 36, it is evident that in the suboxide the lead is 

 combined with precisely half as much oxygen as exists in the oxide. 

 The suboxide may therefore be considered as constituted of 1 atom 

 of oxygen -f 2 atoms of lead. 



Oxalate of tin prepared by pouring oxalic acid into protacetate of 

 tin, yielded by distillation water, oxide of carbon, carbonic acid, and 

 empyreumatic oil. The residue was protoxide of tin of a bright 

 brown colour. — Ibid., p. 264. 



SCIENTIFIC BOOKS. 



Researches in Theoretical Geology. By H. T. De la Beche, F.R.S., 

 V.P.G.S. 



Outline of the Geology of the Neighbourhood of Cheltenham. By 

 R. I. Murchison, F.R.S., V.P.G.S. 



Report of the British Association for the Advancement of Science 

 at Cambridge in 1833. 



Origines Biblicce • or Researches in Primaeval History. By Charles 

 T. Beke. 



