Circular of the National Bureau of Standards, Issue 440U.S. Government Printing Office, 1942 |
From inside the book
Results 1-5 of 100
Page 58
... minutes of arc . ( 4 ) MOUNTING .-- Another factor of great importance , and one that in the past has not been given the attention it deserves , is that of the mounting . The plate should be mounted loosely in a metal frame , the axis ...
... minutes of arc . ( 4 ) MOUNTING .-- Another factor of great importance , and one that in the past has not been given the attention it deserves , is that of the mounting . The plate should be mounted loosely in a metal frame , the axis ...
Page 99
... minutes before switching on the plate power , T2 . For the sake of simplicity of the drawing , the filaments are shown lighted by separate transformers . In practice they may just as well be paralleled on a single 5 - volt winding ...
... minutes before switching on the plate power , T2 . For the sake of simplicity of the drawing , the filaments are shown lighted by separate transformers . In practice they may just as well be paralleled on a single 5 - volt winding ...
Page 116
... minutes shaking , a shaking machine being convenient if large numbers of samples are to be handled . After solution is complete , the clarifying agent is added . The method of clarification depends on the nature and amount of impurities ...
... minutes shaking , a shaking machine being convenient if large numbers of samples are to be handled . After solution is complete , the clarifying agent is added . The method of clarification depends on the nature and amount of impurities ...
Page 117
... provided the duration of the filtration does not exceed 10 or 12 minutes . 2. If the correction for the increase in polarization is. FIGURE 32. - Bates saccharimeter and lamp . Polarimetry , Saccharimetry , and the Sugars 117.
... provided the duration of the filtration does not exceed 10 or 12 minutes . 2. If the correction for the increase in polarization is. FIGURE 32. - Bates saccharimeter and lamp . Polarimetry , Saccharimetry , and the Sugars 117.
Page 118
... minutes . Q should be subtracted from the observed polarization to obtain the true polarization . 3. Practically all ... MINUTE = = $ FIGURE 33. - Curves showing the effect of evaporation on the polarization of raw sugars . adhering to ...
... minutes . Q should be subtracted from the observed polarization to obtain the true polarization . 3. Practically all ... MINUTE = = $ FIGURE 33. - Curves showing the effect of evaporation on the polarization of raw sugars . adhering to ...
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Common terms and phrases
alkaline analysis angle axis beam boiling Brix Bureau of Standards C. S. Hudson calculated carbon cell CHCl3 Chem chloride Clerget coefficient color concentration constant containing cooled copper correction crystals determined deut dextrose dilute direct polarization dissolved electrode equation evaporated filter filtrate flask formula glass glycosides grams H. S. Isbell H₂O halfshade heating hydrochloric acid hydrolysis instrument invert sugar invertase Jackson and Gillis lactose lamp lead acetate levulose measurements melting method methyl alcohol mg mg mg mixture molasses mutarotation nicol nicol prism normal weight obtained optical rotation oscillation oxide percent percentage plane polarized polariscope polarized light potassium precipitate prepared prism quantity quartz quartz control plates raffinose reaction reading reagent reducing sugars refracting saccharimeter salts sample sirup sodium specific rotation substance sucrose sucrose solutions Sugar Scale sugar solution sulfate sulfuric acid temperature tion titration tube vacuo volume washed wave length
Popular passages
Page 158 - If the analyst is in doubt as to the completion of the hydrolysis, allow a portion of the solution to remain for several hours and again polarize. If there is no change from the previous reading, the inversion is complete, and the reading and temperature of the solution should be carefully noted.
Page 181 - Titrate at once with the thiosulphate solution until the brown tinge has become weak, then add sufficient starch liquor to produce a marked blue coloration. Continue the titration cautiously until the color due to free iodin has entirely vanished.
Page 778 - After bringing the solution exactly to the mark at the proper temperature, and after wiping out the neck of the flask with filter paper, pour all of the wellshaken clarified sugar solution on a rapidly acting filter. Reject the first portions of the filtrate and use the rest, which must be perfectly clear for polarization.
Page 250 - In case the sample is too dense to determine the density directly, dilute a weighed portion with a weighed quantity of water, or dissolve a weighed portion and dilute to a known volume with water. In the first instance the per cent of total solids is calculated by the following formula : • WS Per cent of solids in the undiluted material= — • S=per cent of solids in the diluted material.
Page 789 - Receptacles — How sampled. — Sugar in hogsheads and other wooden packages shall be sampled by putting the long trier diagonally through the package from chime to chime, one trierful to constitute a sample, except in small lots, when an equal number of trierfuls shall be taken from each package to furnish the required amount of sugar necessary to make a sufficient sample. In the sampling of baskets, bags, seroons, and mats the short trier shall be used, care being exercised to have each sample...
Page 120 - Add strong ammonium hydroxide with constant stirring until the solution is alkaline to litmus, allow the precipitate to settle, and wash by decantation with water until the wash water gives only a slight test for sulfates with barium chloride solution.
Page 170 - Alkaline tartrate solution. — Dissolve 173 g of Rochelle salt and 50 g of sodium hydroxide in water, and dilute to 500 ml.
Page 155 - Defecate, if necessary, with basic lead acetate in the usual manner, making to volume at the temperature at which the observations are to be made.
Page 177 - By consulting the table it will be seen that the vertical column headed 150 is nearest to Z, 145, and the horizontal column headed 95 : 5 is nearest to the ratio of R to I, 95.1 : 4.9.
Page 783 - Inasmuch as the absorption of sea water or moisture reduces the polariscopic test of sugar, there shall be no allowance on account of increased weight of sugar importations due to unusual absorption of sea water or other moisture while on the voyage of importation.