. Journal. me of the standard tubeof gas. great care must be exercised to avoid heatfrom the body reacliing the tube. .Standardburettes may be kept in one limb of a water leveltilled witli water saturated with nitric oxide, andby raising or lowering the other liml) so as to bringthe level inside the eudiometer lube to that of theliquid outside, the volimie at atmospheric pressurecan be read without toucliing the tube at all(Fig. 4). The movable limb should be kept a littlelower than the other when the reading is not beingtaken, so as to have a somewhat reduced pressurein the gas-tube itself. A
. Journal. me of the standard tubeof gas. great care must be exercised to avoid heatfrom the body reacliing the tube. .Standardburettes may be kept in one limb of a water leveltilled witli water saturated with nitric oxide, andby raising or lowering the other liml) so as to bringthe level inside the eudiometer lube to that of theliquid outside, the volimie at atmospheric pressurecan be read without toucliing the tube at all(Fig. 4). The movable limb should be kept a littlelower than the other when the reading is not beingtaken, so as to have a somewhat reduced pressurein the gas-tube itself. A tube of gas was also keptimmersed in the movable Umb so as to provide forlosses due to changes in temperature and in this manner a standard tube of gas wasfound to have suffered praxtically no change involume after many weeks. The weight of nitric acid may be calculateddirectly from tlie volume of nitric oxide, but it ismuch simpler to compare this volume with thatof the standard tube of Fiu. 4. Let V, be the volume of gas in the standardtube and Vo the volume obtained from the sampleof acid taken of weight W. Now in 20 of the standard solution there it0-330 grm. of NaNOs, corresponding to 0244629grm. of UNO 3. Therefore the percentage of UNO, =24-4629Vo -= Since Vo varies very little, we may take £factor F corresponding to 24-4629 -t-Vq and raalc({â¢a table, allowing for the ordinary variations otemperature and pressure. Then % nNO,=Vâ.F-=-W. An example will show the working of the resultnusing tliis table. Let the volume of nitric oxid<given off from 1-4200 grm. of acid be 97-5 the volume of the standard tulie at that temperature and pressure be 92-2 Then in th<table we read opposite 92-2 the factor F, which ii:given as 0-2053. Hence % HNO, = ^^^^g^oo^^ =18-20%. Vol. XXXV., No. 3.] SA VILL & COXâVISCOSITY OF OILS IN REDWOOD AND OSTWALD VISCOMETERS. 151 Table A. in Natural staQclard uuinber 1 2 3 4 0 6 7 8 9 tube.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
