OCR Text |
Show Platinum Contacts. It Is not an unknown practice among sharp dealers to substitute nickel silver for genuine platinum in ignition contacts. con-tacts. Here is a simple test to discover the imposition. Take a few filings from the contact and place them in a chemical teat tube with a small quantity of strong nitric acid and apply a gentle heat. If they are of nickel silver the filings will dissolve and color the acid green, or if they are plain silver they will dissolve, though a little more slowly. Genuine platinum will not be affected at all by the acid, in fact it can only be dissolved by boiling in a mixture of nitric and hydrochloric acids, called by chemists aqua regla. |