T H E J O U R - Y A L OF I - V D U S T R I A L
Apr., 1913
detail in any standard work. After inversion is complete and while still in the water bath, add I gram powdered zinc, heat for another j minutes, pass through cotton, wash the cotton until I O O cc. is obtained a t 20’ C. Invert Sugar Determi?iatio+z.-To exactly I O cc. of Fehling’s solution, blue, and I O cc. of Fehling’s solution, white, in a 2 5 0 cc. flask, add the solution under test and enough distilled water t o make 50 cc. Boil cautiously upon a square of asbestos, having a central hole, for 2 minutes, fhen cool quickly. Add I O cc. of 2 0 per cent. solution K I , rotate, add I O cc. of 2 5 per cent. H,SO,, then nitrate with -\-I I O thiosulfate. Work rapidly throughout, running in by 3-4 drops at the end. Run a “blanc” upon the Fehling solution, under precise conditions of analysis to determine its value in terms of thiosulfate. Use the table of MeisslI and Hiller t o calculate results. Careful determinations by several chemists have shown that not all of the copper present can be accounted for with cane products, and the following table of factors was been worked o u t :
LVsEL
I
2
3
5
7
i
6
IO
// i2 13
CHART SHOWISG
JL
I?
CASES
/(i
/7
REPORTED IN
BY T H E BROKEN L I S E ;
TABLEO F INVERT SCGARFACTORS
-
Juices
Sugars
Molasses
-
7 - - 7
2
i
Cc. decinormal thiosul- , , f a t e used I 5 0 981 10 0.998 15 1.007 15.5 ... 20 1.016 25 1.045
*
:
Lg
i
7
II I 0.928 0.91’) 1.013 ,
..
1.048
.,.
I’ I
I 0 , 9 5 0 0 926 0,966 0.961 0.Y8Y 1.011
.,
,
1.016 1.030
7
N
n
+
+
I
I’ I
c.
0.996 1.013 1.017
c
.
e *
n
*
-t
II 1
I
0.934
0.960 0,983 1.011 0.988
0.980
...
...
...
...
1.021 0.963
1.020 1.022
1.032 1.04;
1.001 1.002
I/ 0.956 0.988 1.010
1.015 1.001 0.971
Example.-Used in “blanc” titration, 27.7 j cc., in back titration, 6.93 cc., net utilized, 2 0 . 8 2 cc. 0.00636
* Spencer’s “Handbook
20.82 = 0.1324
0.1 3 2 4
gram Cu, --
f o r Cane S u g a r JIanuiacturers,” pp. 129, 130.
=
0.0662
=
2.
W = 8.27j grams material taken for determination. Polarization = 10.08. 0.0662 X roo/8.27; = T = 0.8 per cent., I O O X 10.08/1o.o8 -. 0.8 = 92.7 = R. I O O - 92.7 = 7.3 = I. Since 2 0 cc. of Fehling’s solution were used instead of 5 0 cc., Cui2 or 0.0662 gram must be multiplied by 2 . 5 to find the factor, F., which equals 0.165 gram Cu. By the Meissl and Hiller table, factor = 53.1. Hence 0.1324 X 53.1/8.275 = 0.85 approximate invert. Referring to the above table of corrections results in that of 1.016. 0.85 per cent. x 1.016gives 0.864 per cent. corrected. 765 WESTMINSTER ROAD BROOKLYN, S . Y.
STERILIZATION O F WATER SUPPLY AT TRENTON By H . C. HOTTEI.~ Received January 6, 1913
Statistics issued by Dr. *4. S. Fell, Health Officer of the City of Trenton, show that there have been 100 cases of typhoid fever in the city during the year
TRESTOS,BY
CASES IN
For use where the copper reduced is determined by difference
,-
X
Z i 22 13 I 4 I 5 1 6 17 19 2 4 30 31 32 35 34 35 3 i 37 36
16 I7 2:
O F TYPHOID
I
WEEKS.
CASES
IN
+,:
1911
40 4f f i *3 44 *I
M
47 “8 ’7
rri 54
32
ARE S H O W S
1912 BY T H E SOLID L I N E
1 9 1 2 . For the previous five years the number of cases averaged over 2 5 0 annually. The total for the year 1911 was 302 cases. The highest number of cases reported in any one week in 1912 was 7 while the highest number in 1911 was 24. The drop in the number of typhoid cases is attributed to the use of calcium hypochlorite to sterilize the. drinking-water supply, raw Delaware River water. The chart shows in a graphic manner the decrease in typhoid. The following table shows the wide range between the two years. In 1912 there were only nine weeks in which more than three cases were reported while in 1911 there were 33 weeks in which more than this number were recorded. 1
C l t y Chemist, Trenton, Xew Jersey
T H E J O U R N A L OF I A ’ D U S T R I A L A N D EA;GIiVEERI-VG C H E N I S T R Y
320
Cases each week
1911
1912
0. ....................... 1 . . ......................
3 weeks 6 weeks
12 weeks
3 . . ...................... 3
7 weeks 3 weeks . 3 3 weeks
2 ........................ Above
........................
13 weeks 7 weeks 1 1 weeks 9 weeks
The sterilization plant was installed in Nov., 1 9 1 1 , a t a cost of $4,500 and has been in continuous operation since that time. I t is not intended, however, t o always treat the water in this manner, as plans have been completed and the contract awarded for the erection of a mechanical filtration plant, with a capacity of 30,000,000 gallons of water daily a t a Cost Of $330,000. When first installed the hypochlorite plant was under the supervision of the New Jersey State Board of Health but in March, 1 9 1 2 , the city took charge of the operation of the plant. The hypochlorite purchased averages about 35 per cent. available chlorine, and treatment was begun with a strength of 0.4 part to the million of available chlorine. This was found to be insufficient and was later raised to 0.8 part and during the year 1 9 1 2 has varied from 0.7 t o I part per million with a daily pumpage of about 2 0 , 0 0 0 , 0 0 0 gallons. I n commercial terms this means that 1 7 to 2 4 pounds of calcium hypochlorite has been added t o every million gallons of water pumped. Tests of the treated water show a material decrease in the number of bacteria. Ninety-eight per cent. of the tests for colon bacillus, in one cc. of the raw water gave positive results. I n the treated water the positive tests for colon bacillus in one cc. have averaged 2 0 per cent. The average 2 0 ’ bacteria reduction per cc. of water has been 94.1 per cent. The hypochlorite plant consists of a small twostory frame building. The lower floor is divided into two rooms, a chemical storage room and a machinery room; the second floor comprises the operating room and office. The machinery and apparatus consists of two chemical dissolving tanks, two chemical solution tanks, one orifice tank and one receiving tank, the last-named tank being connected by a supply pipe t o a grid located in the sluice gate manhole in the intake, at a point just before the intake enters the pump well a t the main pumping station. From this point the water is pumped to a I I O , O O O , O O Ogallon distributing reservoir, it requiring about 90 minutes t o reach the reservoir from the pumping station. The chemical is dissolved t o a 2 per cent. solution and the orifice controls the rate (in gallons per minute) at which the solution is added t o the raw water. The plant is under the supervision of Chief Engineer Lenox of the pumping station and, as it is necessary t o have some one in constant attendance, i t requires the services of three men working on eight-hour shifts. That the hypochlorite treatment is being used extensively in drinking-water supplies of American cities is attested by the report of the Ohio State Board of Health.1 It states t h a t information has been received in regard t o the drinking-water supply of 99 cities of over 2 5 , 0 0 0 population in the United States, 1
Ohio State Board of Health, Mouthly Bulletin, Oct.. 1912.
Vol. 5 , No. 4
and t h a t 40 per cent. of these cities are using hypochlorite t o purify the water. THE DETERMINATION OF MINERAL AGGREGATE IN BITUMEN PAVEMENTS B y C. C. ~ ’ L O U G H L I N Received Sovember 21, 1912
The experiments described below were carried out as a comparison of the filtration and centrifugal methods for the determination of mineral aggregate in bituminous substances. The following samples were used for both methods: Refined Trinidad asphalt.. . . . . . . . . . . . 5 1 . 60y0 bitumen Refined Bermudez asphalt.. . . . . . . . . . . 9 6 . 22y0 bitumen California “D” grade asphalt. . . . . . . . . California “G” grade asphalt, . . . . . . . .
99.947’0 bitumen 98 .86y0 bitumen
The Filtration Method.-Ten grams of the asphaltic mixture were weighed and placed in a z 1 j 2 ” funnel, which contained a 9 cm. Schleicher & Schull No. 597 filter paper; a 2 5 0 cc. Erlenmeyer flask was used to catch the filtrate. Carbon bisulfide was run onto the sample until absorbed, but no more, and allowed t o stand until i t softened and settled into the filter; i t was washed again until the solvent nearly filled the filter. This operation was repeated until the filtrate came through clear and then finished with two washings of petrolic ether. The latter operation was found necessary t o clean the aggregate of some of the lighter oils, which seemed t o remain even after repeated washings with carbon bisulfide. The aggregate was allowed to drain and when dry brushed onto a watch-glass. The filter paper was placed in a porcelain crucible, burned a t a low heat, and then added t o the main residue on the watchglass. The combined samples were dried, cooled in a desiccator and weighed, the weight of residue being the aggregate and the difference being the bitumen. The above method was found to take from 4 to I O hours, and in some cases as long as 2 0 hours. This method used about 2 5 0 cc. of solvent. The Centrifugal Method.-In this method the Dulin Rotarex, designed by R. S. Dulin, Chemical Engineer of the City of Portland, Oregon, was used. This apparatus consists of a n aluminum bowl receptacle for the sample, which is 3 1 / ~ in ” diameter and equipped with a suitable cover; the cover is fastened on by means of a funnel-shapdd screw, through which the solvent is added; this also allows the escape of gases. The above is enclosed in a copper shell, provided with a spout at the bottom side, through which the waste liquors drain ; the shell is provided with a two-piece cover, the smaller one being removed t o add additional solvent. The machine is run by electric motor directly underneath. The filter of proper diameter is placed between the bowl and cover, and when the machine is in operation the solvent is thrown to the sides, passing through the filter, carrying with i t the soluble matter. Fifty grams of sample were placed in the bowl, the filter put in place, the cover fastened on and 50 cc. of solvent added; the machine was rotated until
