T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
Jan., 1918
large dr0p.l T h e coil is carefully dried high above t h e flame or on a radiator, taking care t o avoid spattering. T h e unknown solution is matched with standards b y means of t h e brilliancy of t h e line. An accuracy of from 5 t o I O per cent is easily obtained b y different observers. BUREAUO F SOILS WAhHINGTON, D. c.
T h e following examples will explain t h e calculation required for adopting t h e Sachs-LeDocte or Kruger sugar pipettes t o lime cake analysis: A Sachs-LeDocte pipette delivers 1 7 7 cc. of lead solution and uses a normal weight of 26 g. Therefore, 2 0 0 cc. of solution must be added t o t h e dry matter of t h e lime cake, and if it is assumed t h a t t h e cake contains jo per cent moisture, we have 13 IO 177 = 2 0 0 cc. As it is necessary t o a d d acetic acid or ammonium nitrate t o decompose saccharates, t h e strength of acid is so adjusted t h a t I O cc. are required. When t h e filtered sample is polarized in a 2 0 0 mm. t u b e twice t h e scale reading is t h e per cent sugar in t h e cake. With t h e Kruger automatic pipette t h e normal weight is adjusted t o t h e size of t h e pipette; for instance, if t h e pipette delivers 123.6 cc., t h e normal weight is 41. 2 g. for beets, and t h e same weight is used for lime cake. T h e amount of solution t o a d d t o t h e d r y matter of t h e lime cake is 158. 5 cc., a n d if t h e lime cake contains approximately j o per cent of moisture t h e solution is made up of 2 0 . 6 14.3 123.6 = I 5 8 . 5 cc. Here 1 4 . 3 cc. of acetic acid solution a r e used, a n d t h e polarization in a 200-mm. t u b e is t h e per cent sugar in t h e cake. If t h e moisture content of t h e cake varies appreciably from jo per cent t h e volume of acetic solution added is adjusted accordingly. When “free” sugar is t o be determined, water is added instead of acetic acid. By t h e use of normal lead acetate solution i n t h e place of subacetate solution, no acetic acid need b e added, b u t i n t h a t instance a different weight of lime cake should be used i n order t o give t h e proper dilution.
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A QUICK M E T H O D FOR L I M E CAKE ANALYSIS By ALFREDN. CLARK Received November 5 , 1917
The usual procedure i n lime cake analysis has been t o weigh out 50 g. of t h e sample i n a sugar weighing dish, a d d acetic acid, mix t o a t h i n m u d i n t h e weighing di3h, transfer t h e contents t o a 200-cc. flask, a d d lead subacetate solution, and fill t o t h e mark with water. All t h e textbooks describe a method similar t o t h e above, a n d in which a flask is used. Such a procedure has four serious drawbacks which are avoided i n t h e method described below. With t h e flask method, lime is liable t o foam over t h e sides of t h e sugar dish when acid is added; it is difficult t o thoroughly mix i n such a small dish without spilling; there is danger of spilling when transferring from t h e weighing dish t o t h e flask; and thewhole procedure is a slow,disagreeable one. The: writer weighs t h e sample of lime cake i n a counterbalanced, nickel-plated, copper beaker of about 300 cc. capacity, adds t h e calculated volume of acetic acid solution from a pipette, mixes with a small pestle, adds a charge of lead subacetate solution from a Sachs-LeDocte or a Kruger pipette, again mixes with a pestle, a n d pours onto a filter. T h e dish is large enough t o avoid foaming over, and t h e mixture is not transferred from t h e weighing dish until ready t o filter. 1
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A No. 27 wire B. & S. gauge, coiled seven times around a s/sr rod,
makes a good coil.
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900 N. WASHINGTON AVENUE LANSING, MICHIGAN
I RECOVERY OF LIGHT OILS AND REFINING OF TOLUOL 1 ~~~
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Report prepared by t h e Bureau of Standards in response t o numerous inquiries for information regarding recovery of light oils and t h e refining of toluol. This report was submitted to, and revised in accordance with suggestions of the committee, consisting of representatives of t h e Public Service Commissions, municipalities, manufacturers of gas, and makers OF toluol recovery equipment, organized under the chairmanship of Dr. E. B. Rosa of t h e Bureau of Standards at the request of t h e conference which met a t t h e Bureau July 31, August 1 a n d 2 , 1917. PART I-THE TECHNICAL RELATION OF T H E QAS I N D U S T R Y T O T H E M I L I T A R Y NEEDS OF T H E NATION
usually been considered profitable. Even now, althou8.h several months have elapsed since the United States entered the war, I . HIGH EXPLOSIVES MANUFACTURED FROM GAS BY-PRODUCTS- comparatively few city plants are equipped to recover these The importance of high explosives in the present war has been materials, but the prospects are that in the near future they amply demonstrated. While nearly all kinds of explosives are must do so if the requirements for high explosives are as great used in some way, those which are most in favor for filling as is anticipated. Major Burns of the Ordnance Department high explosive shells are manufactured from benzol and toluol, at the conference held at the Bureau of Standards on August I which substances have their most important commercial stated that the Army is dependent upon toluol for the manusource in manufactured gas of one kind or another. The gas facture of T. N. T. for shell filler. The amount of toluol needed industry thus becomes directly and vitally connected with the depends upon the number of men engaged and how engaged. conduct of the war and a survey of the demands which will be The present estimates are that toluol for shell filler will be made upon it, and its preparedness in a technical way to meet needed in the coming year for our own army, for the allies, and the navy at a rate considerably in excess of the present or these demands, is very important at the present time. anticipated supplies from works under construction. There is 2. CITY GAS PLANTS MUST SUPPLEMENT COKE-OVEN PRODUCat the present time about 4 million pounds per month of T. N. T. niTroru--The constituents of illuminating and fuel gas which are trating capacity and sufficienttoluol is not now available to utilize important in the manufacture of explosives a t the present time it; it is therefore now impossible to place more orders for T. N. T. are benzol and toluol, especially the latter. The removal of primarily because more toluol is not available. It is probable these constituents from the gas which is a by-product of coke- that any and all explosives including the picrates will be necesoven plants has been practiced for some time. Plants manu- sary eventually. facturing city gas, however, have not generally removed these substances from the gas since they contribute to its light- and 3 . MRNTJFACTURINO PROCESSES I N USE I N THE UNITED STATES heat-giving qualities and the substitution of other substances -The manufactured gas distributed in the United States is of t o maintain the gas quality up to prescribed standards has not three principal kinds: Coal gas, carbureted water gas, and oil gas.
