Nov., 1918
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
91 1
LABORATORY AND PLANT METHODS OF ANALYSIS USED IN THE COAL-TAR INDUSTRY. 111-HEAVY AND MIDDLE OILS B y J. M. W ~ r s s Received September 9, 1918
H E A V Y OIL TESTS T E S T HP-WATER'
ACCURACY-0,002.
KoTE-The correction factor, 0.00075, does not apply with equal accuracy t o all oils, but serious error due t o its use will be avoided if the precaution of avoiding unnecessarily high temperature is observed. The factor 0.00075 and its method of use are approximations.
APPARATus-same as given under Bz (see Fig. 11, Paper I , THISJ O U R N A L IO , (1918), 735). METHOD-200 cc. of oil shall be measured in a gradTEST H4-SPECIFIC GRAVITY (WESTPHAL) uated cylinder, and poured into a copper still, APPARATUS-WeStphal balance. 2 j cc. glass cylinallowing the cylinder t o drain into the still for der. several minutes. Attach lid and then the clamp, METHOD-The balance shall be set u p and adjusted using a paper gasket slightly wet with oil, around the flange of the still. Heat shall be applied by means so t h a t the plummet when suspended t o swing freely of the ring burner, which shall be placed just above in air exactly balances the beam. A reading shall the level of the oil in the still a t the beginning of the then be taken in water a t I 5 . j " C. and if the balance test, and gradually lowered when most of the water is properly made and adjusted, this will be unity. A has distilled over. The distillation shall be continued second reading in oil a t 15.j" C. gives the specific until the vapor temperature, indicated b y the ther- gravity directly. PREcAuTIoNs-If the reading in water a t I j. jo C. mometer with the bulb opposite the off-take of the is not unity when the balance is adjusted in air so connecting tube, reaches 2 0 5 " C., t h e distillate being , t h a t the plummet balances the beam, the balance collected in the separatory funnel. When the distillation is completed, and a clear separation of water and shall not be adjusted in water, but the oil reading oil in the funnel'has taken place, the water shall be divided by the water reading shall be taken as t h e read by volume and drawn off; and any light oil dis- specific gravity. Boiled distilled water shall be used. Care shall be tilled over with the water shall be returned t o the oil in the still after i t has cooled sufficiently. The de- taken to see t h a t the wire from which the plummet is hydrated oil from the still shall be used for the dis- suspended is immersed in both oil and water t o the same point when the instrument is in balance. Care tillation and other tests. must be taken t o see t h a t the plummet is clean and TEST H3-SPECIFIC GRAVITY (SPINDLE)' dry before immersion. APPARATUS-Hydrometer and cylinder (See Fig. KoTE-If the specific gravity is t o be taken a t a 11, Paper I, THIS JOURNAL, IO (1918)) 735). Two temperature above 15.j" C., a reading must be taken hydrometers with ranges 1.00 t o 1.08 and 1.07 t o in water a t the same temperature and the specific I . 1 5 will suffice. These shall be calibrated a t 1 5 . 5 ' gravity a t t / t o C. obtained. This may be conC. (60" F.). verted into specific gravity a t t o / I j. 5 " C.by multiplyME'rHOD-The oil shall be brought t o a tempera- ing by the density of water a t t"/15.5' C. These ture 'of 38" C. (100' F.) and the determination shall density figures for water may be found in reference be made a t t h a t temperature unless the oil is not en- books such as Van Nostrand's ChemicalAnnual. To tirely liquid a t 38' C. The cylinder shall be filled calculate from 38'/38O t o 38'/15.5' C. the factor is with dry oil, the latter stirred, and the tempera- 0.99385. From the foregoing it will be readily seen t h a t ture noted. The hydrometer shall be inserted and i t is incorrect t o calculate the specific gravity a t the reading taken. I n case the oil requires t o be 3 8 '/I j . 5 " by dividing the reading in oil a t 38 " by the brought t o a higher temperature t h a n 38" C. in order reading in water a t I 5 . 5 O C. as is occasionally done. t o render it completely fluid, it shall be tested a t the TEST H ~ - I K S O L U B L E I N BENZOL^ lowest temperature a t which i t is completely fluid, All matter as t o apparatus, method, notes, and preand a correction made b y adding 0.0007j t o the observed specific gravity for each degree Centigrade cautions as given under B 7 2 apply t o this test on these materials. above 38O, a t which the test is made. ACCURACY-0. 2 per cent. PRECAUTIONS-Before taking the specific gravity iiOTE-At least I O g. of oil shall be taken for the test. the oil in the cylinder should be stirred thoroughly with a glass rod, and this rod when withdrawn from the TEST H6-RETORT DISTILLATION' liquid should show no solid particles a t the instant APPARATUS-Retort: This shall be a tubulated of withdrawal. Care should be taken t h a t the hydrom- glass retort of the form and approximate dimensions eter does not touch the sides or bottom of the cylin- shown in Fig. XI1 with a capacity of 2 5 0 t o 290 cc. der when the reading is taken, and t h a t the oil sur- The capacity shall be measured by placing the retort face is free from froth and bubbles, 1 See
1917
A. S. T.M.Method D-38-17, A. S. T. M. Standards adopted in
See A. S. T.M. Method D-38-17, A. S. T. M. Standards adopted in
1917.
THISJOURNAL, 10 (1918), 736.
912
T H E J O U R N A L O F 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 Vol.
IO,
No.
II
with t h e bottom of t h e bulb and t h e end of t h e offtake in the same horizontal plane, and pouring water into the bulb through t h e tubulature until i t overflows the off-take. The amount remaining in the bulb shall be considered its capacity. Condenser tube: This shall be a suitable form of tapered glass tubing of the following dimensions:
.
dividing temperature for each fraction. When the temperature reaches 35 5 O, the flame shall be removed from the retort, and any oil which has condensed in the off-take shall be drained into the 35 j ' fraction. NOTES-The residue shall remain in the retort with the cork and the thermometer in position until no vapors are visible; i t shall then be weighed. If the residue is t o be further tested, i t shall then be poured Diameter of small end, 12.5 mm.; permissible variation, 1.5 mm. Diameter of large end, 28.5 mm.; permissible variation, 3.0 mm. directly into the brass collar used in the float test or Length, 360.0 mm.; permissible variation, 4.0 mm. into a tin box and covered and allowed to cool to air Shield: An asbestos shield of the form and approxi- temperature. Care must be taken not t o pour at a mate dimensions shown in Fig. XI1 shall be used t o temperature high enough t o cause loss of oil vapors. protect the retort from air currents and to prevent If the residue becomes so cool t h a t it cannot be poured radiation. This may be covered with galvanized readily from the retort, i t shall be re-heated and comiron, as such an arrangement is more convenient pletely melted by holding the bulb of the retort in hot and more permanent. water or steam and not by t h e application of a flame. Receivers: Erlenmeyer flasks of 50 t o I O O cc. For weighing the receivers and fractions, a balance capacity are the most convenient form. accurate t o at least 0.05 g. shall be used. Thermometer: This shall conform to specification During the progress of the distillation the thermomas given under C7. eter shall remain in its original position. N o correcAssembly: The retort shall be supported on a tion shall be made for the emergent stem of the thertripod or on rings over two sheets of io-mesh gauze, 6 in. mometer. square, as shown in Fig. XII. It shall be connected When any measurable amount of water is present to the condenser tube by a tight cork and the ther- in the distillate i t shall be separated as nearly as possimometer inserted in a tight cork in the tubulature,, ble and reported separately, all results being calculated with the bottom of the bulb l/2 in. from the surface on the basis of dry oil. When more than i per cent of of the oil in the retort. The exact location of the water is present, water-free oil shall be obtained by thermometer bulb shall be determined by placing a separately distilling a larger quantity of oil, returnvertical rule graduated in divisions not exceeding l / l e ing to the oil any oil carried over with the water, and in. back of the retort when t h e latter is in position for using dried oil for the final distillation (see Hz). the test, and sighting the level of the liquid and the G R A V I T Y FRACTIONS (WESTPHAL)l point for the bottom of the thermometer bulb. The T E S T H7-SPECIFIC APPARATUS-Aspecial type of Westphal balance is distance from the bulb of t h e thermometer t o t h e outlet end of the condenser tube shall be not more than obtainable, designed for testing very small quantities. 24 nor less than 2 0 in. The burner shall be protected However, the ordinary type of Westphal balance can from draughts by a suitable shield or chimney (see be adapted t o testing small fractions by the use of a special plummet. The plummet can readily be made Fig. XII). in the laboratory from a piece of ordinary glass tubing 7 mm. outside diameter, sealed at the end, and melting into the glass, where sealed a short platinum wire. After cooling place 9 t o I O g. of mercury in the tube, making a column 35 t o 40 mm. high. Seal O R the tube within 2 0 mm. of the top of the mercury column with blowpipe flame. The plummet shall have a length of about 5 5 t o 6 0 mm. over all and shall weigh between I O and 1 2 g. NETHOD-The weights necessary t o balance t h e plummet in air and in water of t h e required temperature shall be noted and similarly the weight necessary to balance the plummet in oil a t the same temperature. FIG. XII-ASSBMBLY OF DISTILLATION TESTFOR HE.~VYOIL A. S.
T.M. D-38-17
METHOD-Exactly I O O g. of oil shall be weighed into the retort, the apparatus assembled, and heat applied. The distillation shall be conducted a t the rate of a t least one drop and not more than two drops per second, and the distillate collected in weighed receivers. The condenser tube shall be warmed whenever necessary t o prevent accumulation of solid distillates. Fractions shall be collected at the following points: 210°, 2 3 s 0 , 270') 315', and 355' C. The receivers shall be changed as the mercury passes the
If a = weight to balance in air b = weight to balance in water t o t o c = weight to balance in oil at t o Specific gravity
to/to
= 'Za
b-a
PRECAUTIONS-When using the small plummet, special care is needed t h a t the adjustment of the balance be accurately made. NOTE-FOr corrections from t O / t OC. t o t O / ~ j .5' C., see note under H4. 1 See paper by J. M. Weiss, THIS JOURNAL, 7 (1919, 21, and A. S. T. M. Method D-38-17, A. S. T.M. Standards adopted in 1917.
Nov., 1918
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
This method is adapted t o fractions which are liquid under 60" C. and may usually be applied t o the 2 3 5 " t o 31 j " fraction. TEST
~8-SPECIFIC
GRAVITY
FRACTIONS
(PLATINUM
PAN)
All matter under B62 applies to this test on this material. NoTE--This method is adapted to solid and semisolid fractions such as are usually obtained from 315Oto 3 5 j 0 C . TEST Hg-FLOAT
TEST O N RESIDUE'
All matter as t o apparatus, method, precautions and notes, as given under C 8 , applies t o this test on these materials. TEST Hg-FLOAT
T E S T 'ON R E S I D U E M A T E R I A L 3
All matter as t o apparatus, method, precautions a n d notes as given under C8 applies t o this test on these materials. T E S T HIO-COKE4
APPARATUS-Hard glass bulbs as shown in Fig. X I 1 shall be used. METHOD-The bulb shall be warmed slightly t o drive out all moisture, cooled in a desiccator, and weighed.. Then the bulb shall be heated again by placing i t momentarily in a n open Bunsen flame, the tubular placed underneath the surface of the oil t o be tested, and the bulb allowed t o cool until sufficient oil is sucked in t o fill the bulb about two-thirds full. Any globules of oil sticking t o the inside of the tubular shall be drawn into the bulb by shaking, or expelled by slowly heating it. The outer surface shall be careEully wiped off and the bulb reweighed. This procedure will give about I gram of oil. A strip of thin asbestos paper about l / 4 in. wide and about I in. long shall be placed around the neck of the bulb and the two free ends caught close up t o the neck with a pair of crucible tongs. The oil shall then be distilled off as in making ordinary oil distillation, starting with a very low flame and conducting the distillation as fast as can be maintained without foaming. When oil ceases t o come over, the heat shall be increased until the highest temperature of the Bunsen flame is attained, the whole bulb being heated red-hot until the evolution of gas ceases, and any carbon sticking t o the outside of the tubular is completely burned off. The bulb shall then be cooled in a desiccator, weighed, and the percentage of coke residue calculated on water-free oil. PRECAUTIONS-Be careful t o heat the oil slowly a t the start t o avoid spurting. If the oil contains over 2 per cent of water i t should be dried before testing. The oil must be thoroughly liquefied and uniform throughout. See paper by J. M. Weiss, THISJOURNAL, 7 (1915), 21, and A. S. T. M. Method D-38-17, A. S. T. M. Standards adoptedsin 1917. *THISJOURNAL, 10 (1918), 736. * See standard method of the Am. Wood Pres. Aseoc. adopted in 1916 and A. S. I?. M., D-38-17, tentative method, A. S. T. M. Proceedings 1917, Part 1, p . 526. 4 Ibid., p. 828.
913
NOTES-A large diameter cork with a cup-shaped hole cut in the center forms a convenient holder in which t o weigh the bulb. When a stock of bulbs is received, one or more should be given a heat test to determine hardness. Occasionally bulbs have been found too soft, therefore melting below the temperature required t o coke the oil and thus producing low results. TEST HII-TAR
ACIDS (CON-
TRACTION M E T H O D )
A P P A R A T u s-Tar-acid separatory funnel, type I (see Fig. X I I I ) . Tar-acid separatory funnel, type 2 (see Fig. XIV). Distillation apparatus. METHOD-100 cc. of oil shall be placed in a distilling apparatus such as is used I I I under test Fg and distilled C.L. until a t least 95 per cent of distillate has been obtained or until the vapor temperature has reached 400' C. The entire distillate shall be transferred t o a tar-acid separatory I designed for funnel-type oils which have 2 5 per * cent t a r acids or over, or type 2 for oils containing h less than this amount. The funnel with the oil shall be placed in a water bath and kept a t a constant temperature of 60" C. until no change in volume takes place. It shall then be extracted with successive portions of jo CC. each of I O per cent caustic soda solu- tion until no further diminution in volume occurs. I The soda shall be added t o the oil, the whole thoroughly shaken, then returned to the bath a t 60" C. I and allowed t o settle completely. *fter settling is FIG.XIII-DETAIL
1 *
OF TAR-ACID SEPARATORY FUNNEL, TYPE1
complete, the soda layer A-Ground glass stopper shall be drawn off and the B-Capacity given from stopcock up Of Oil C-Ground glass stopcock noted. When the point of no further contraction is reached the diminution in volume of the oil shall be considered as tar acids. Noms-In some cases (such as creosote t a r solutions containing small amounts of acids), there will be insufficient material t o bring the oil up into the
914
T H E J O U R N A L O F 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 Vol. graduated section of type 2 separatory funnel. I n such cases, sufficient tar-acid-free, clean, heavy naphtha may be added t o dilute the oil and bring it within the graduated portion. If this is done, the extracted oil cannot be used for subsequent dry salt tests but a n additional portion must be extracted for this purpose. This test is recommended for all general work in oil specifications and general comparative tests, but gives results slightly higher than the true tar-acid content of the oil. The reason for this is t h a t soda withdraws from creosote oil certain compounds which are not subsequently liberated from the soda solution in the form of an oil. These substances are evidently acid in nature but not phenolic bodies. TEST
HIP-TAR
(LIBERATION
ACIDS METHOD)
APPARATUS-same as used under H I I . Water a n d t a r separatoryfunnel (see Fig. 11, Article I,
THIS (I918),
METHOD-I00
FIG.XIV-SEPARATORYFUNNELPOR ACID DETERMINATION, TYPE2 A-Ground glass stopper B-s/s in. drilled hole C-Ground glass stopcock
IO
JOURNAL,
735. CC.
Of
oil shall be distilled as prescribed under HII. (Where the content of t a r acids is very low, a distillation may be made on 2 0 0 cc. so as t o obtain a more accurate test.) The oil shall be shaken in a separatory funnel with successive 50 cc. portions of I O per cent caustic soda or until no more t a r acids are removed. The well-settled separated carbolate shall be acidified in a small beaker with 40 per cent sulfuric acid, taking care to keep the mixture cool
IO,
No.
II
a t all times. (If the content of tar acids is under 5 per cent, use the water in t a r separatory funnel a n d measure carefully into it I O cc. of "Hiflash" naphtha. The liberated t a r acids and sulfate solution are then poured through this layer of naphtha several times, drawing the material off a t the bottom of the funnel into the original beaker and pouring i t back into the top of the funnel. This washes out the beaker and allows all the tar acids t o be absorbed by the naphtha.) The funnel shall then be allowed t o stand until the layers separate perfectly clearly when the sulfate solution shall be drawn off and the increase in volume of the naphtha taken as the dry t a r acids present. When the content of acids is over 5 per cent, the same procedure can be used, measuring 6 ; cc. of "Hiflash" naphtha into the tar-acid separatory funnel, type 2. PRECAUTION-A~~results must be figured on the basis of dry oil. NOTES-In distilling 2 0 0 cc. of oil, i t is necessary t o use a distilling bulb of about 500 cc. capacity. "Hiflash" naphtha may be obtained from The Barrett Company Chemical Department. This method gives approximately the amount of tar acids that can be recovered from a n oil in practice. Results by this method are usually about go per cent of the results obtained by the method as given under H I I . TEST HI3-HEMPEL DISTILLATION' APPARATUS-Forest Service Hempel flask.2 Condenser tube (see Fig. 11, Article I, THIS J O U R N A L , IO (1918),735). Thermometer? graduated from o o t o 400'; specifications as under Cg. Glass beads. Asbestos shield. The apparatus assembly is shown in Fig. XV. METHOD-The empty flask shall be tared, 2 5 0 g. of melted, well-shaken oil introduced, and a second weight taken. The flask shall be supported on a n asbestos board with a slightly irregular opening of very nearly the largest diameter of the flask, and the apparatus assembled as in Fig. XV. The distillation shall be run a t the rate of I drop per sec., and fractions collected in weighed flasks between the following temperatures: Up t o 170°, 170'to 2 0 5 O , 205'to 2 2 5 ' ) 2 2 5 ' t o 235', 2 3 5 ' to 245', 245' t o 255', 2 5 5 " t o ~ 8 . 5 285' ~) t o 295') 2 9 5 ' t o 3 0 5 ' , 305' t o 3 2 0 ' ~ and if feasible, 320' t o 360'. The character of the fractions and their weights shall be recorded. PREcAwrIoNs-Drafts on the distilling apparatus must be avoided. NoTE-In noting the character of the fractions, t h e operator should observe the apparent amount of salts separating a t room temperatures and roughly approximate the nature of the fraction, e. g., solid, half solid, liquid, etc. TEST
HI&-INDEX
O F REFRACTION O F FRACTIONS
ApPARATUS-Zeiss-Abb6 refractometer. METHoD-water a t 60' c. shall be circulated through the water jacket which surrounds the main 1
2
Adapted from Forest Service Circular 112, U. S. Dept. Agriculture A. H. T.28220, E. & A. 3072.
.
Nov., 1 9 1 8
T H E J O U R N A L O F I N D U S T R I A L A-VD E N G I N E E R I N G C H E M I S T R Y
prisms. After the temperature of the water in the jacket has been brought t o this point, the prisms shall be separated and a few drops of the oil t o be tested placed between them. They are then brought together and locked in position. The prisms shall now be rotated until the field of view consists of a light and dark portion. The telescope is provided with a recticule which can be brought into exact coincidence with the observed border line between the light and dark field. The compensator prisms are rotated until a sharp 'line of demarcation is produced. The index of refraction shall be read on the scale through the eye piece on the left side of the refractometer.
FIG.
XV--ASSEMBLY OF
HEMPELDISTILLATION TEST
FOR
HEAVYOIL '
FOREST SERVICE METHOD
PRECAUTIOljS-The
temperature must be kept at The lenses and prisms should be kept perfectly clean. Special lens paper should be used f o r this purpose so as t o avoid scratching or damaging the surfaces. Take care t h a t the reflector does not show the line of a window sash which may be mistaken for the border line. Such a reflection can be detected b y moving t h e mirror, when the true line does not move. 60" C. throughout the test.
NoTEs-The light is regulated by the reflector beneath the prisms until suitable illumination is obtained. If the line cannot be produced, either there is insufficient oil between the prisms or the index of refraction of the material lies outside the range of t h e instrument. With each refractometer is supplied a solid disc of known refractive index for use in checking t h e original adjustment of the instrument. Directions for its use accompany the instrument.
TEST H I j-SULFONATION
91.5
RESIDUE'
APPARATUS--Milk bottles, A. H.T. 33,964, E. & A. 4,450. Centrifuge: Any milk bottle centrifuge will do; there are many types; refer t o any apparatus catalog. A convenient type where only few tests are run is A. H. T. 33,936,E. & A . 1,883. Where many tests are being handled, A. H. T. 33,940, E. & A. 1,978 is better. METHOD-Ten grams of the fraction of oil t o be tested shall be weighed into a Babcock milk bottle. T o this shall be added 40 cc. of 37 N sulfuric acid (total SOS, 80.07 per cent), I O cc. a t a time. The bottle with its contents shall be shaken for 2 min. after each addition of I O cc. of acid. After all the acid has been added the bottle shall be kept a t a constant temperature of from 98' t o 100' C. for one hour, during which time it shall be shaken vigorously every I O min. A t the end of an hour the bottle shall be removed, cooled, filled t o the top of the graduation with ordinary sulfuric acid, and then whirled for 5 min. in a Babcock separator. The unsulfonated residue shall then be read off from the graduations. The graduated portion of the bottles measures 2 cc. and is divided into IO major graduations. These major graduations are subdivided into either j or I O smaller divisions. The reading, expressed in terrfis of major divisions, multiplied by' 2 , gives per cent directly. PRECAUTIONS-The unsulfonated residue should be a clear transparent oil. If there is a n apparent residue of dark or gummy appearance, the sulfonation is probably incomplete and the test should be repeated. The addition of the acid should be regulated so t h a t the mixture ceases t o heat up onshaking, before another portion is added. If acid is added too quickly, foaming results. Sometimes the material will s t a r t t o ioam on removal from the hot bath. Immersion in cold water will usually stop the foam. Proper strength of sulfuric acid is essential. ACCURACY-0. I per cent of amount taken, t h a t is, 0.01 cc., unless the per cent residue exceeds 5 , when 0.5 per cent variation is allowable. xoms-Occasionally a solid residue of white paraffin is obtained. I n this case the bottle should be warmed sufficiently t o melt the paraffin and re-whizzed. The reading may be taken while the material is liquid. This method differs from the original Forest Service method in t h a t the oil is weighed and not measured. On solid fractions an accurate measurement is impossible. Therefore, we have specified weight and our per cent result really represents cc. per I O O g. If a real per cent b y volume is required the result should be multiplied b y the determined specific gravity of the oil fraction and the result reported as per cent by volume (calculated). The 37 N acid should contain 80.07 per cent total so^. I t is made b y mixing analyzed ordinary concentrated sulfuric acid with analyzed fuming sulfuric acid in the proper proportions. It is best t o run a check test on the mixture t o insure the fact t h a t the strength is correct. 1
Adopted from Forest Service Circular 191, U. S. Dept. Agriculture.
916
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING T E S T HI6-TAR
BASES
This test shall be carried out exactly as described under H I I , using 2 0 per cent sulfuric acid instead of I O per cent caustic soda. As there are rarely more than 5 per cent of bases in any coal-tar oil, the tar-acid funnel, type 2 , should be used for this purpose. TEST HI7-DRY
SALTS AT
4.5'C.
(4O'F.)
APPARATUS-copper beaker, 500 cc., A. H. T. 21,812, E. & A. 7 50. Buchner funnel (a suitable type is A. H.T. 28,616, E. 8~ A. 3,254). Filter flask (a suitable type is A. H. T. 28,248, E. & A. 3,090). Letter press. Vacuum pump. METHOD-The whole sample of oil after the extraction of tar acids as in H I I or H I Z shall be used. (Note t h a t this represents I O O cc. of the original oil.) It shall be placed in the copper beaker and cooled with stirring t o 4 . 5 ' C. (40' F.) in a suitable bath and held at t h a t temperature for 15 min. The contents of the beaker shall then be quickly filtered off on the Buchner funnel and the oil removed from the solids as quickly as possible. The solid cake shall then be removed from the filter and pressed re$eatedly in a letter press between strips of blotting paper or filter paper until only a trace of oil is given up to the paper. The solids shall then' be weighed. Their weight in grams divided by t h e specific gravity o f the oil gives t h e per cent by weight of dry solids. PRECAUTIONS-TO quicken the filtering, a spatula should be used t o press the solids down in the funnel and avoid channeling. ACCURACY* I per cent.
C H E M I S T R Y voi. Io,
NO.
II
$or oils with limpid points below o o C. a special thermometer graduated from -30° to S O o c*may be wed. The lowest temperature Obtainable by the above freezing mixtures is about c* If no separate a t this temperature a very small amount of powdered naphthalene may be added t o seed out the solids. If no separation can be obtained in this manner, report should be made "no separation Obtainable." MIDDLE OIL TESTS
The usual tests made are water, specific gravity, distillation, tar acids, dry salts, tar bases, and limpid point, and these are made in the same manner as the corresponding tests given above under heavy oil. THEBARRETT COMPANY 17 BATTERY PLACE,NEW YORKCITY
THE POLARISCOPE SlTUATION AND THE NEED OF AN INTERNATIONAL SACCHARIMETRIC SCALE By C. A. BROWNE Received August 5, 1918
Among the many claims which are being made upon industry as a result of the present war there are probably none more pressing than the demand for certain kinds of scientific apparatus. I n the sugar industry alone there is a most serious shortage of polariscopes, refractometers, and colorimeters, and with the inability t o obtain certain repairs the number of such instruments available for technical control is constantly growing less. Seventy years ago practically all of the sugar testing apparatus used in the United States came from TEST HIS-LIMPID POINT France, and although most excellent saccharimetric APPARATUS-TeSt tube, 5 in. 10% by 1 in. inside instruments have always been obtainable from t h a t diameter. T'hermometer reading from O o t o 80' as country, nearly all of t h e polariscopes used in the used in D6. Distillation apparatus. sugar and food laboratories of the United States a t METHOD-Fifty CC. of dry oil shall be taken in a Clean the present time were manufactured in Germany or distilling apparatus such as used for naphthas and * Austro-Hungary. There are several explanations for light oils and distilled to (Eyyfiess, no thermometer this preference for instruments of German manufacbeing used. The condenser water shall be kept hot ture: (I) Since the time of Liebig the technical to avoid solidification of the distillate. schools and universities of Germany have been most The distillate shall be well mixed and 30 CC. trans- frequented by American students, the result being a ferred t o the test tube. This shall then be cooled, greater familiarity on the part of scientists in this using a freezing mixture (3 Parts of shavedice t o 1 Part country with instruments of German origin. ( 2 ) At of Salt) if necessary. During cooling the Oil shall be the time when many of our industries were established kept agitated by stirring with the them10meter and German emigrants were the most available for certain Cooling continued Until a Strong Separation Of Crystals positions and German methods and apparatus were has taken Place. The tube Shall now be r m ~ o v e d thus naturally introduced. (3) German manufacfrom the cold bath and warmed a t the rate of 2 o c- turers have been much more active than their French per minute, continually stirring, until all Crystals competitors in bringing their instruments to the atdisappear. The temperature registered by the ther- tention of the ~~~~i~~~ public. mometer a t this moment shall be recorded as the jviti1 t h e entrance of the United States into t h e limpid point. present war the importation of scientific apparatus PRECAUTIONS-If free water should be present in from G~~~~~~ and Austria came t o an end. Those the Oil, this might be mistaken for crystals, hence who needed polariscopes were thus obliged, as 7 0 dry oil must be used. years ago, t o turn to France, the birthplace and original ACCURACY=k 2 ' c. home of this instrument. The optical establishments of NOTES-The best method t o maintain the rise a t France were SO taxed, however, with the manufacz 0 C. per min. is to place the tube in a beaker of water ture of periscopes, field glasses, gun sights, etc., t h a t or brine 3 'to 5 ' c. above the oil temperature and warm no time could be spared for manufacturing other the bath, a t about the 2' C. rate. apparatus, although the instrument-makers of France
