00931cam a22002771a 4500 e 20000544 DLC 20260227111211.0 890405s1920 dcuaf f000 0 eng e 20000544 (OCoLC)19497253 DLC WvU DLC premarc LC1045 .A25 no. 41 Virgin, R. Z. (Robert Zerubabel) Coal-mine ventilation. Washington, D.C. : Federal Board for Vocational Education : Govt. Print. Off., 1920. 63 p., [3] leaves of plates : ill ; 24 cm. Bulletin / Federal Board for Vocational Education ; no. 41 Trade and industrial series ; no. 11 Cover title. "Prepared by R.Z. Virgin"--P. 5. "November, 1919." Mine ventilation. United States. Federal Board for Vocational Education. 20395 20395