208 ANNUAL OF SCIENTIFIC DISCOVEKY. 



out showing any evidence of cracking ; these tubes are made, in the 

 first instance, by casting them of a large size, and the diameter is 

 then reduced by drawing them in the same manner as wire. The 

 extreme ductility of phosphorized copper is shown by the production 

 of a long tube with a bore as fine as a needle, which has been re- 

 duced down by drawing from a nine-inch casting. Brass manufac- 

 tured from phosphorized copper also retains many of its valuable 

 properties. 



New Alloy ; a Substitute for Silver. The Paris Cosmos describes 

 a new alloy composed of block tin three hundred and seventy- 

 five parts, nickel fifty-five, regulus of antimony fifty, and bismuth 

 twenty parts, which M. Trabuc, of Nismes, proposes as a substi- 

 tute lor silver, as it resists the action of vegetable acids. It is pre- 

 pared by placing in a crucible one-third of the tin, together with 

 the nickel, antimony, and bismuth ; over this is laid another third of 

 the tin, and above that a layer of charcoal. The crucible is then 

 closed and brought to a reddish-white heat, and its contents examined 

 with a red-hot rod of iron to ascertain if the nickel is melted and the 

 antimony reduced. The last portion of tin is then made to pass 

 through the charcoal, and the mixture well agitated. 



Food Preservative. A patent has been recently granted in Eng- 

 land for preserving articles of food by introducing into tin cans con- 

 taining the food a substance for which oxygen has a greater affinity 

 than for the meat or other article of food under preservation, and which 

 at the same time shall be in no way detrimental to it. Such an agent, 

 the patentees state, is sulphate of soda. 



Reduction of Chromium and Manganese. In the course of some 

 experiments with amalgam of sodium, the idea occurred to Mr. C. W. 

 Vincent that it might be employed to advantage as a ready means of 

 reducing some of those metals which are not readily obtained by 

 ordinary metallurgical processes. By adding to a solution of the 

 chloride of chromium an amalgam of sodium, he found that, although 

 there is a considerable waste of sodium, nevertheless an amalgam 

 remains of chromium, which, on distillation in a tube retort filled 

 with naphtha vapor, yields this metal in a finely-divided state. Mr. 

 W. B. Giles has shown, in a note in the Philosophical Magazine, 

 that when an amalgam of sodium is placed in a saturated solution of 

 pure protochloride of manganese a rapid action takes place, hydrogen 

 is evolved, and, finally, an amalgam of manganese remains. For 

 the details of the experiment which led Mr. Giles to infer that the 

 powder which he obtains is metallic manganese, we must refer to his 

 note. He states that the same results appear to take place with 

 cobalt. 



Coloration of Iron. M. Thirault, pharmaceutist of St. Etienne, 

 has been investigating the natural oxides of iron. In addition 

 to ordinary rust, there is another oxide (the ferrosoferric oxide) 

 but slightly susceptible of alteration. Iron covered with this latter is 

 protected from rust even in moist air. This varnish is produced by 

 the use of the following mixtures: 1. Chloride of mercury and sal- 

 ammoniac. 2. Pcrchloride of iron, sulphate of copper, nitric acid, 

 alcohol, and water. 3. Per- and protochloride of iron, alcohol, and 

 water. 4. Weak solution of sulphide of potassium. These solutions 



