The principles of hygiene : a practical manual for students, physicians, and health officers / by D.H. Bergey.

  • Bergey, D. H. (David Hendricks), 1860-1937.
Date:
1901
Catalogue details

Licence: In copyright

Credit: The principles of hygiene : a practical manual for students, physicians, and health officers / by D.H. Bergey. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

    71/532 (page 69)
    the preferable form, because it is less liable to get out of order. The best form of cowl consists of a fixed down- cast tube with expanded, trumpet-shaped mouth, above which is a conical cap, the apex of which is turned upward (Fig. 9). By means of this arrangement the Fig. 10.—Ail- introduced at bottom, discharged at top. aspirating force of the wind may be utilized to main- tain a fairly constant current of air either in one direction or the other. The movement produced by the unequal weights of masses of air of different temperatures takes place through Fig. II.—Air introduced on side, discharged at top. the ordinary openings, and to some extent through the por- ous walls of a room; but, as the doors and window^s may be closed and the movement be largely arrested, other open- ings should be provided to secure ventilation. The problem to be solved is—Which is the most satisfactory