I012
T H E JOL‘RNAL O F I N D C 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
S, which is connected, as shown in Fig. I , directly through a shut-off valve t o t h e gas main. Gas may be a d m i t t e d or shut off from the entire system b y turning t h e main valve, or t h e individual burners may be regulated separately. The plate T, which supports t h e distilling flasks, is made of so-called “asbestos lumber,” but this material was not found t o be entirely satisfactory since i t had a tendency t o break after i t had been used for a time. A more satisfactory support could have been made of sheet iron covered with a thick layer of ordinary asbestos board, since the asbestos would serve as a sort of shock absorber in the case of a n y bumping of the flasks. A piece of asbestos lumber is placed in front of and bolted t o t h e condenser jackets in order t o prevent heating of t h e water in the condenser b y radiation of heat from the Bunsen burners. T h e advantages of this type of distillation apparat u s are: I-Each condenser is entirely separate a n d may be removed as a whole, or in part, in case of injury, without interrupting t h e working of the remainder of the system. This is a decided advantage over t h e common type of condenser where a t a n k contains t h e spiral block-tin tubes of all the flasks in use, since, if one of t h e tubes or a n y portion of t h e t a n k leaked, i t necessitated t h e dismantling of the whole system in order t o make necessary repairs. 2-It is possible by means of t h e “stop a n d waste” cock not only t o use a n y desired number of t h e units of t h e system, b u t also t o regulate the flow of water through t h e different units. 3-The apparatus is simple in construction a n d made entirely of inexpensive materials such as a plumber would ordinarily have on hand. T h e author wishes t o express his appreciation t o Mr. R . D. hlilner for his interest a n d kind suggestions in connection with t h e construction of this apparatus. LABORATORY OF NUTRITION INVESTIGATIONB OFFICE OF
EXPERIMENT STATIONS
u. s.DEPARTMENT O F AGRICULTURE, WASHINGTON A CONVENIENT COLOR CAMERA By C. M. CLARK Received June 3. 1914
This camera may easily be made by a n y one with a little skill in carpentry a n d a few moments leisure, or i t can be cheaply had of a n y cabinet maker. It has been in use in this laboratory for some time a n d has given satisfaction. The lens cost a b o u t 50 cents. T h e box is best made of white pine. It is 160 mm. long, 1 0 0 mm. wide, a n d I O O mm. high, inside measure. I n one end is cut a slit 2 0 mm. wide, extending t o within I O mm. of t h e inside t o p a n d bottom of t h e box; this slit is closed with a piece of either ground or milk glass, as preferred, b u t if milk glass be used it must not be over 2 mm. thick. A piece of light blue glass m a y be set inside t h e other t o neutralize t h e yellow rays where artificial light is used. T h e slit must be exactly centered. I n t h e other end, a n d exactly centered, is cut a hole 60 X 6 0 mm., a n d i n this is set a collar made of a b o u t 6 mm. material a n d a b o u t 50 mm. long, with a b o u t I O mm. projecting outside t h e box. I n this collar
Val. 6, No.
12
slides a tube made of the same material a n d about I O O mm. long, carrying a t its outer e n d a 60 mm. sq. cap in which is set a crown glass lens of approximately 160 mm. focus. T h e lens should be about 35 mm. in diameter a n d stopped down t o a b o u t 2 j mm. The cover of the box is loose, a n d has a collar fitting inside t h e box t o hold it in place. I n this cover, exactly opposite the glass closed slit, a n d about 20 mm. from the edge, is cut a n aperture large enough t o perm
front Elevaf/h
-
lonpifudina/
Section
A - Lens
E-Cap to C
D - Co//ar
d -Brocef o r o
c - slidiny tube
E - Cover e - Co//a r to support € F - Glass filling s/if or reor
G - Co/arto keep tudes upright mit t h e two comparison tubes t o enter freely, yet without play; this opening m a y be felt lined. A collar having a like aperture m a y be placed underneath it, on t h e floor of the box, t o steady t h e tubes. T h e inside of t h e box is, of course, painted dead black. T h e advantages of this camera are t h a t , as t h e comparison tubes set exactly in front of t h e slit a n d occupy its entire width, all light passes through t h e m , while t h e lens enables one t o bring the tubes into exact focus; and, as only one eye is used, there is less chance of the left h a n d tube looking t h e darkest. The sliding tube should be rubbed with graphite. CHATTANOOGA CHEMICAL LABORATORY CHATTANOOGA. TENN.
IMPROVED METHOD FOR THE DETERMINATION OF NITROGEN IN STEEL B y L. E. BARTON
Received July 7 , 1914
T h e method usually employed for t h e determination of nitrogen in steel is t h e one first published b y A. H. Allen a n d modified b y Prof. J . W. Langley. When operating this method as described by Blair, “Chemical Analysis of Iron,” i t was observed t h a t t h e sample a n d standard for comparison, when treated with Nessler reagent, developed colors differing in quality or tone-the sample developed an orangeyellow a n d t h e standard a brownish yellow color-which renders comparison difficult a n d results inaccurate. Another difficulty sometimes encountered, which makes comparison impossible, is t h e clouding of solutions after addition of Nessler reagent upon standing for t h e specified t e n minutes, a n d is particularly noticeable with t h e first 50 cc. distillate, in which t h e ammonia
T H E J O U R N A L O F I N D U S T R I A L ALVD E N G I N E E R I N G C H E X I S T R Y
Dec., 1914
is comparatively concentrated. However, with properly prepared Xessler reagent, this latter trouble should n o t occur. Experimental work was undertaken with t h e object of developing a more accurate method of determination as a result of which a modification of t h e above mentioned method was adopted. By this modification of t h e method, t h e sample a n d standard distillates are prepared under similar conditions, a n d when treated with Nessler reagent develop colors identical in quality or tone, b u t proportional in intensity t o t h e ammonia present. If t h e Nessler reagent is carefully prepared a n d works properly, t h e color i n sample a n d standard will develop almost instantly a n d is fully developed in less t h a n one minute. The solutions treated with such Nessler reagent remain clear or do not cloud appreciably on standing for t e n minutes; however, t h e comparison is best made after standing one minute a n d all possible difficulty due t o clouding avoided. The determination is also rendered more accurate b y taking a larger sample for analysis and using a n aliquot part of t h e total distillate for comparison. T h e reagents are prepared exactly as described in Blair’s “Chemical Analysis of Iron,” seventh edition. [NOTE-The ammonia-free hydrochloric acid may also be prepared thus: Dilute concentrated hydrochloric acid t o specific gravity 1.10 and, without Hydrochloric acid of this strength addition of sulfuric acid, distil it. distils without change in concentration. T h e first 100 cc. distillate from one liter of acid will usually contain all the ammonia and is rejected; the portions distilled thereafter are collected for use but must, of course, be teste’d as usual t o make sure they are free from ammonia.] M E T H O D OB D E T E R M I N A T I O N
O F SAMPLE-In a distilling flask Of t o Ijoo cc. capacity, fitted with separatory funnel a n d connected with condenser, place 40 cc. prepared caustic soda solution; a d d joo cc. distilled water, a n d distil until t h e distillate gives no reaction with Nessler reagent. Dissolve a j g. sample of t h e steel in 40 cc. of a m monia-free hydrochloric acid, a n d b y means of t h e separatory funnel a d d t h e solution slowly t o t h e contents of t h e distilling flask, washing in finally with ammoniafree water. Distil a n d collect Ijo cc. of t h e distillate in a gfaduated flask. Cork t h e flask a n d set aside. Experience has shown t h a t I jo cc. of distillate will contain all t h e nitrogen i n t h e sample. DISTILLATION
1000
1
P R E P A R A T I O X O F STANDARD--AfteT distilling t h e sample-the apparatus then being free from ammonia, b u t containing t h e residue of sample a n d reagents2 j cc. of standard ammonium chloride solution and I jo cc. of ammonia-free water are added t o t h e contents of t h e flask, and distillation continued until a standard distillate of ~ j cc. o is collected i n a graduated flask. A s before, t h e single distillate will be found t o contain all t h e ammonia from 2 5 cc. of standard solution. To t h e standard distillate is added 6 cc. of Nessler reagent; and since t h e standard ammonium chloride solution is equivalent t o O.OOOOI g. nitrogen per cc., I cc. prepared standard distillate is equivalent t o 2 j X O.OOOOI = 0.0000016 g. nitrogen per cc. = 156 0.00016per cent nitrogen on a one gram sample. I t should be noted t h a t t h e preparation of a single standard distillate is sufficient for determination of nitrogen in several samples if t h e comparisons are being made a t t h e same time. COMPARISON A N D DETERMIXATION-TO make t h e determination, 30 cc. of s a m p l e distillate (equal t o one g r a m of sample) are placed i n one of a pair of Nessler jars and t h e color developed b y addition of I cc. Nessler reagent. The standard a n d sample are allowed t o stand one minute t o fully develop t h e color. I n t o t h e other jar t h e standard distillate is run from a burette until t h e colors in standard a n d sample jars are of t h e same intensity; t h e final comparison is made after bringing t h e contents of the jars t o the same volume b y addition of ammonia-free water t o one o r t h e other. The number of cc. standard distillate multiplied by 0.00016gives t h e percentage of nitrogen in t h e steel. N I . . . . . 0.0038 0.0037 0.0037 2 . . . . . . 0.0035 0.0035 3 . . . . . . 0.0037 0.0037
N O
PERCENTAGES OF SITROGEN FOUND N So. No. h ‘ h’o. 0,0038 10 7. 4 . . . . . 0,0032 0,0043 0,0032 0.0037 11 8. 5 . . . . . 0.0043 0.0040 0.0043 0.0038 9 6 . . . , . 0 0040 0.0043 0 0040
,...
By BERWHARD C. HESSE Received October 29, 1914
At the very beginning, it should be pointed out that the world’s market in coal-tar dyes as i t stands today comprises, in round numbers, goo distinct and different chemical substances which are made by the aid of 300 products of transformation, themselves not dyes, of I O products obtained or obtainable from coal-tar by distillation, refrigeration, expression or the like. Therefore, actually and in reality, the present coal-tar dye industry comprises no fewer than 1,200 different products and as
’
Address delivered before the Board of Directors of the General Chemical Company, in New York, October 23, 1914.
N 0.0035
0.0035 0,0033 0.0038 0.0037 0.0037
....
The results shown in t h e above table indicate t h e accuracy of t h e method t h u s modified. TITANIUM ALLOY MANUFACTURING Co. NIAGARA FALLS, Pi. Y.
I
ADDRESSES T H E lNDUSTRY OF T H E COAL-TAR DYES’ AN OUTLINE SKETCH
1013
many or more different processes of manufacture and requires many hundred different sets of apparatus of varying capacities and of differing kinds for many hundred different operations. A manufacturing problem comprising so many independent and yet interlaced units of manufacture and production has, therefore, varied elements of complexity; to what extent this is true will appear later on. T H E N A T U R E O F COAL-TAR
In the production of coal-tar, suitable for use in the coal-tar dye industry, there is made on the average from 100 parts of coal: 72 parts COKE 6 parts TAR(liquid and solid distillate)
22 parts GAS
The gas and coke are not considered here; thedistillate, amounting t o 6 per cent of the weight of the coal, is the portion of these products with which we are here concerned.
