Since 1913 D has acquired 21 domestic metal container companies as well as numerous others engaged in the packaging business, including producers of flexible packaging; a manufacturer of polyethylene bottles and similar plastic containers; 14 producers of paper containers and paperboard; four companies making closures for glass containers; and one -- Hazel-Atlas -- producing glass containers. D was the second largest company in the metal container field, shipping approximately 33% of all such containers sold in the United States. During 1956, D acquired not only the Hazel-Atlas Company but also Robert Gair Company, Inc. -- a leading manufacturer of paper and paperboard products -- and White Cap Company -- a leading producer of vacuum-type metal closures for glass food containers. Hazel-Atlas Glass Company was the Nation's third largest producer of glass containers. P brought this action seeking a judgment that the acquisition violated § 7 of the Clayton Act 1 and requesting an appropriate divestiture order. Trying the case without a jury, the District Court found that P had failed to prove reasonable probability of anticompetitive effect in any line of commerce, and accordingly dismissed the complaint at the close of P's case. The trial court found that the metal can industry, the glass container industry, and the plastic container industry were at issue. The trial judge held that under the guidelines laid down by Brown Shoe, the Government had not established its right to relief under § 7 of the Clayton Act. The court found that the can industry and the glass container industry were relevant lines of commerce. Beyond these two product markets, P urged the recognition of various other lines of commerce, some of them defined in terms of the end uses for which tin and glass containers were in substantial competition. The court, for the most part, rejected P's claim that existing competition between metal and glass containers had resulted in the end-use product markets urged by P. P failed to make 'appropriate distinctions . . . between inter-industry or overall commodity competition and the type of competition between products with reasonable interchangeability of use and cross-elasticity of demand, which has Clayton Act significance.' This appeal followed.