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1-013

0.39

deg. C.

PAUK.

170°-230° 230°-270° 270°-330°

40.4

5.1

54.5

1.05
30.0

1-8 13.2

14.8

22.3

46.2

1.7

1.008

0.24

100.0

16.0

9.0

75.0

Washed and Refined oil

27.0

29.6

46.5

63.0

NOTES. The high percentage of low boiling unsaturated bodies is noticeable. The fraction 170-270 is rich in phenolic bodies.

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2nd Fraction.

210

Temperature.

220

230

240

250

260

270

280

290

300

4th Fraction.

Per cent.

3.6

5.5

10.9

19.3

27-8

36.6

46.1

52-2

57.8

62.2

65.2

67.8

70.5

Per cent.

6.8 18-0

26.8

37.6

48.8

58.4

65.2

83.2

TABLE 10.-Distillation ranges of tar acids from fraction 170—270°C.

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THE MAURYPUR SALT WORKS. BY J. A. DUNN, B.SC., D.I.C., F.G.S., Assistant Superintendent, Geological Survey of India.

con

THE

HE method of salt recovery used at Maurypur differs siderably from the usual processes and, as it appears not to have been previously described, a short account

of it may be worthy of record.

Introduction.

The salt works are about 8 miles west of Karachi on the seaward edge of the Moach plain. Some 1,800 acres of this plain lie between the high water mark of the fortnightly spring tides and the still higher tides of June and December; of this area 180 acres form the present salt works.

The climate is almost ideal for rapid solar evaporation. The mean annual rainfall at Karachi is only 7-64 inches, normally distributed over 9 days; generally the air is comparatively dry and seldom still; while the mean daily maximum temperature is 84°F.

The works are surrounded by an earthwork ("bund") 8 feet high as a protection against flooding during storms or abnormally high tides. Along the seaward edge of this a trench, 2,200 yards long, 7 feet wide and 4 feet deep, has been excavated. This communicates with the sea and supplies sea water through sluices to similar trenches within the works. The main inside trench has been cut completely round the inner side of the "bund." The total length of trenches within the works is 5,800 yards. Letting to the salt workers ("lunaris") is done by plots, each consisting of 20 salt pans, 29 feet square. The pans are surrounded by small

""

bunds," a few inches high, made from a fine impermeable clay, and this, well tamped, is also used for the beds of the pans. Nearly 600 wells have been sunk in the works. The first 4 feet of the strata passed through consist usually of sandy loam with thin bands of clay; below this, to at least 15 feet, is a clayey loam. Brine in a well may be met with at a depth of anything from 1 to 17 feet, the variation corresponding roughly with its distance from a trench. It is raised by means of a tub, suspended by a rope from a bamboo pole pivoted 3 feet from the ground, and is run directly into the

Method of salt recovery.

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