236 Miscellaneous Intelligence. 



16. Pure ProiO' Salt of Iron. — A solution of protoxide of iron, 

 without any admixture of peroxide, may be obtained by putting 

 iron into an aqueous solution of sulphurous acid, and suffering 

 the mixture to remain for a short time without contact of the air. 

 When a solution of the ferro-cyanate of potash is added, a per- 

 fectly white precipitate is formed, which is the proto-ferrocyanate 

 of iron. — Phillips, Phil. Mag., N. S.,\. 72. 



17. Action of Potassium on Oxalates. — When well-dried oxalate 

 of lead, mixed with very small portions of potassium perfectly 

 freed from naphtha, is heated in the bottom of a glass tube, air 

 being carefully excluded by excess of the oxalate, a violent detonation 

 suddenly takes place, before the heat is sufficiently great to effect 

 the decomposition of the oxalate, when no potassium is present. 

 The tube is spotted with metallic lead, the potassium is oxidized, 

 and there is no carbon deposited. An examination of the gas 

 resulting from this instantaneous decomposition may elucidate 

 the nature of the oxalates, but hitherto the apparatus employed 

 has always been broken by the explosion. Oxalate of copper, 

 treated in the same way, has always occasioned strong detona- 

 tions, and metallic copper appears. — Jour, de Phar., Phil. Mag. 

 N. S., i. 145. 



18. Analysis of the Triple Prussiate of Potash. — Mr. Phillips, 

 by carefully experimenting with the crystallized triple prussiate 

 of potash, obtained the following proportions per cent, of three 

 of its elements : — 



Iron 13.58 



Potassium 36.75 



Water ! 12.50 



the remaining 37.17 parts are assumed, according to the analysis 

 of Berzelius, to be cyanogen. The nature and composition of 

 the salt, which he considers as most probable, is as follows : — 



6 atoms carbon 36 



3 „ azote 42 



3 „ hydrogen 3 



1 atom oxygen 8 



1 „ iron 28 



117 = 1 atom ferro-cyanic acid 



2 atoms potash 96 



213 



Viewing this as the constitution of the salt, it is a di-ferrocyanate 

 of potash, or composed of one atom of sand and two atoms of 

 base.— PM. Mag. N. -S., i. 110. 



19. Preparation of Medicinal Chloride of Soda. — Mr. Pay en 

 has published a process, by which he prepares tlii^ substance of 



