This publication contains 12,554 analyses of gas samples from oil and gas wells and natural gas pipelines in 39 states and 24 foreign countries. These gas samples were collected in the period 1917-80 as part of the Bureau of Mines survey for helium occurences. The gas analyses contained herein were made by several methods over the period covered. Analytical work on samples collected early in the period was done on the orsat apparatus. The one-cut apparatus and four-cut fractional distillation equipment were added later. In 1949, a mass spectrometer was acquired and used for all gas analyses made after that time. Helium analyses throughout the period covered were made on special helium analytical equipment designed and built by the Bureau of Mines helium operations laboratory.