. Public health laboratory work, including methods employed in bacteriological research, with special reference to the examination of air, water and food contributed . Fig. 2.—Chemical balances. After the addition of each successive accretion ofweight the result must of course be tested, but beforeany further addition or removal is made the scalesmust be brought to rest upon their supports, or theapparatus may be put out of gear. Each of the weights is marked, as the plan of the B 2 4 LABORATORY WORK. box will best show (fig. 4). The larger brass weightsrepresenting grammes, the next in size d
. Public health laboratory work, including methods employed in bacteriological research, with special reference to the examination of air, water and food contributed . Fig. 2.—Chemical balances. After the addition of each successive accretion ofweight the result must of course be tested, but beforeany further addition or removal is made the scalesmust be brought to rest upon their supports, or theapparatus may be put out of gear. Each of the weights is marked, as the plan of the B 2 4 LABORATORY WORK. box will best show (fig. 4). The larger brass weightsrepresenting grammes, the next in size decigrammes,the nfext centigrammes, and small forceps are used forpicking up and applying them to the pan. The milli-grammes are added by a little piece of bent wire, whichis carried by means of a sliding rod moving just above. Fig. 3.—Box of chemical weights. the level of one of the cross-beams, which latter willbe observed to show ten markings numbered from oneto ten. By sliding the rod which supports the bentwire up to, say the marking No. 5, and then turning it
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherphiladelphiablakis
