A manual of practical hygiene for students, physicians, and health officers . rawn up and dissi-pated ; in the case of the atomizer, the liquid into which the tube dipsis lifted and blown into spray. This influence is utilized and assistedby various forms of cowls placed over outlet flues; some of these, 480 HABITATIOSS, SCHOOLS, ETC. however, although they seoni to be an aid, are really a hindrance tothe outtloNV, as may eiit^ily be demonstrated. In Figs. 43 and 44 are shown forms of cowls which offer someassistance to the aspiratory inllueuce of winds, and in Fig. 45 is shownanother very po]
A manual of practical hygiene for students, physicians, and health officers . rawn up and dissi-pated ; in the case of the atomizer, the liquid into which the tube dipsis lifted and blown into spray. This influence is utilized and assistedby various forms of cowls placed over outlet flues; some of these, 480 HABITATIOSS, SCHOOLS, ETC. however, although they seoni to be an aid, are really a hindrance tothe outtloNV, as may eiit^ily be demonstrated. In Figs. 43 and 44 are shown forms of cowls which offer someassistance to the aspiratory inllueuce of winds, and in Fig. 45 is shownanother very po]iular kind, the rotary cowl, which offers an obstructionto the passage of air. As the wind causes the top to revolve, the im-pression is made that work is being performed ; that in its revolutionsit is creating a suction which causes an upward current of air. As amatter of fact, however, it is doing no such work, but is, on the con-trary, interposing an obstacle to the passage of air. This may easilybe demonstrated by measuring by means of an anemometer the amount Fig. Aspirating cowl with vane. of air discharged through the flue during a given period while the re-volving top is in place, and again during an equal period while it isremoved. The difference between the results obtained will invariablybe in favor of the period during which the cowl is absent. Other forms of cowls, constructed so that their outlets are turned bymeans of a vane away from the wind, are useful in assisting a form is shown in Fig. 46. By reversing the position of thevane, the mouth of the cowd is turned toward the wind so that the flueis converted into an inlet for fresh air. NATUIiAL VI:NTILATI<)N. 4X1 Natural Ventilation. V<iiiil;iiir(iccc(ls IVoiii the o|)ci;i( ion of ii;itiir:il isknown iis niiiiiiiil \(iil Ihl ion. Ior (Ik; alt;iiiiiii< iit of iIh- lar^chtroHulls, (!S(! lorcrs mil I hr uHsiHtcid to tlic; (!x(-stac-KiS lo llicir adioii >o far as may l)
Size: 1338px × 1866px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishe, booksubjecthygiene
