

Chemical Science. 167 



16. Combustion by Blow-pipe under Water. — Mr. Skidmore, of 

 New York, has remarked that the flame of the oxy-bydrogen blow- 

 pipe may be made to burn under water. All that is required is to 

 introduce it slowly, so that the flame shall not recede into the vessel. 

 In this situation the flame is globular ; wood put into it burns, and 

 wires are ignited, and Mr. Skidmore thinks it may be very importantly 

 applied as a submarine instrument of naval warfare, no difficulties 

 being presented which may not easily be overcome. 



17. Composition of James s Powders. — Mr. Phillips finds James's 

 powders, purchased from Messrs. Newbery's, St. Paul's Church- 

 yard, to consist of 



Peroxide of antimony .... 56.0 



Phosphate of lime ..... 42.2 



Oxide of antimony, impurity, and loss . . 1.8 



100. 

 The quantity of protoxide of antimony contained in the powder was 

 so small, " that it would have been nearly impossible to have ascer- 

 tained its weight."— Ann. Phil. N. S. vi. 189. 



18. Adidteration of Ultramarine. — The following remarks on the de- 

 tection of impurities in ultramarine are by Mr. Phillips, and arc briefly 

 extracted from a paper, by that chemist, on the colouring matter of 

 lapis lazuli. 



Genuine ultramarine loses its colour when put into an acid leaving 

 insoluble matter of a dirty white colour, and affording a colourless 

 solution. It is not injured by boiling in solution of potash. It is not 

 injured by being heated. 



If it be adulterated with blue verditer, upon being heated it will 

 become immediately greenish, and eventually black ; when put 

 into an acid, a greenish or bluish solution is obtained, which, on the 

 addition of ammonia, becomes of a deep blue colour. The bluish acid 

 solution will deposit copper upon iron, and, if much verditer be 

 present, an effervescence will be produced by the action of the acid on 

 it. If Prussian blue be present, heat will cause it to darken very 

 much; when boiled with a little alkali in solution, the colour will 

 become browner, and if there be not too much alkali, the solution 

 obtained will precipitate a solution of iron of a deep blue colour. If 

 indigo be present, heat will volatilize it in the form of a blue vapour, 

 and sulphuric acid will not destroy the colour of the indigo. Smalts 

 may be detected by their resisting the action of acids. Thenard's blue 

 may be distinguished in a similar way. 



Mr. Phillips has failed, like many other chemists, in ascertaining 

 the colouring matter of lapis lazuli, but he has almost shewn that 

 it cannot be a metal or metallic compound. He rather inclines to 

 the opinion that it is due to a peculiar non-metallic substance, of 

 what nature h uncertain.— Ann, Phil. N S. vi, 34. 



