January 15, 1929 – W. Helburn to Irving Langmuir January 15, 1929 – W. Helburn (Helburn Thompson Company) to Irving Langmuir re: planning trip to the Laurentians (to be joined by H. Smith Johannsen) Share thisClick to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on Pinterest (Opens in new window)Click to share on LinkedIn (Opens in new window)
