United States v. Tower & Sons

Tungstic acid, produced in the United States, was exported to Canada in the condition of an impalpable yellow powder. The *136purpose of the exportation was to use the article in the manufacture of tungsten wire for incandescent lamp fillings. The processes applied in Canada are several. It is first dissolved in ammonia and the resultant insoluble materials filtered out. This rejected.material is called an “insoluble residue” and consists of small lumps of clay-like material said to contain tungsten, lime, and other impurities. This is one of the substances imported and the'subject of this…