Sessional_Paper_1907 — Page 888

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Table showing comparative strengths of Red Earth and Sand Mortars exposed to the conditions specified herein.

Description of Briquette.

1.-Lime 1 volume, Red Earth 2 volumes,

2.--Lime 1 volume, Red Earth 2 volumes, but placed under

water after 24 hours in air,

3.-As (2) after 72 hours drying in air,

4.-Lime i volume, Red Earth volumes, and immediately

put under water to set, *

5.-As (4),

Do..

6.-Lime volume, Sand 2 volumes,

7.

do.,

8.-As (6) but placed under water immediately,

9.-As (6) but placed under water after 72 hours drying in

air,

10.—As (1) mixing with ordinary care only,

11.

Do..

do.,

After 14 days. After 28 days.

Pounds.

81

Pounds..

91

99

25

79

111

41

52

81

92

25

29

28

32

Did not set.

6

After 28 days. After 56 days.

44

61

57

58

*The wooden moulds used in this experiment contracted and weakened the briquettes.

The results show conclusively that red earth with good lime takes a better mortar than does sund, also that red earth mortar on account of its setting under water is far better suited to this climate than is the sand variety,

MINERALOGICAL.

10. Every variety of coal put on the Hongkong market is examined with a view of affording information to the public. Indian (Lodna) coal has the following composition in 100 parts :-

Moisture,

Volatible Combustible Matter, Fixed Carbon, Ash,

1.21

18.94

71.89

8.46

100.00

The results show that this is one of the best Eastern coals.

11. An increasing number of ores and of metals has been examined. Most of the metals were various qualities of Chinese tin, of which from 4,000 to 6,000 tons annually pass through Hongkong from Mongtze, Yunnan. The refining of this tin is now one of Hongkong's small industries. The process of purification is carefully done and is quite successful. It is hoped that, despite counter attractions in the mode of carriage from the mines, this tin may still be dealt with in Hongkong. As the trade and refining has now been carried on here for five years, there seems to be a good prospect of its continuance and increase.

12. An examination of twenty cent silver pieces from the Canton Mint shewed them to contain in 1,000 parts :-

Silver,

Lead,

Gold,

Copper,

800.20

1.20

.19

198.41

1,000.00