M 121
The samples of fresh milk which were found to be adulterated, had in most cases been diluted with water. The samples of cheese returned as adulterated had been made from other than full-cream milk. The tinned fish samples were contaminated with metallic tin in excess of the permitted units.
MINERALOGICAL ANALYSES.
296 samples of metals and minerals were examined during 1931 as against 332 in 1930. The nature of this work is shown below:--
Metals 1931 1930 Minerals, 1931 1930 Tin 96 109 Wolfram.... 72 59 Antimony 0 2 Gold ... 1 3 Manganese Bismuthite....... 1 Aluminium Molybdenite 2 Silver Chromite 1 0 Iron Galena 0 Nickel 0 Graphite 1 Lead 2 Antimonite. 1 Alloys Coal 117 32 Tin .... 2 Other ores. 4 13 Total 100 118 Total 196 214The reduced number of samples of tin and wolfram is due to the depressed state of commerce during the year. The increased number of coal samples analysed is due to the chemical control of Government coal purchases introduced during the year. It is reported that this chemical control has resulted in considerable monetary savings since it was introduced.
Water Supplies.
Of the 1348 samples of water examined during the year, 240 were samples of filtered and unfiltered water taken at the filter plants, and the remaining 1108 were from taps in houses from all parts of Hongkong and Kowloon. In addition to these 24 samples of sewage effluents were examined.
Complaints of a chlorine taste in certain supplies having been made, experiments were made in the Laboratory to ascertain the concentration of chlorine necessary to cause a perceptible taste. It was found that 0.3 parts per million could be detected in the cold and 0.2 parts if the water were heated. Concentrations of 0.1 per million and under appeared to be undetectable by taste or odour.
M 121
The samples of fresh milk which were found to be aduiter- ated, had in most cases been diluted with water. The samples of cheese returned as adulterated had been made from other than full-cream milk. The tinned fish samples were contamin- ated with metallic tin in excess of the permitted units.
MINERALOGICAL ANALYSES.
296 samples of metals and minerals were examined during 1931 as against 332 in 1930. The nature of this work is shown below:--
Metals
1931 1930
Minerals,
1931 1930
Tin
96
109
Wolfram....
Antimony
0
2
Manganese
Gold ...
I
Bismuthite.......
721
59
3
1
Aluminium
Molybdenite
2
Silver
Chromite
1
0
Irou
Galena
0
Nickel
0
Graphite
1
Lead
2
Antimonite.
1
Alloys
Tin ....
2
Coal
117
32
Other ores.
4
13
Total
100 118
Total
196 214
J
The reduced number of samples of tin and wolfram is due to the depressed state of commerce during the year. The increased number of coal samples analysed is due to the chemical control of Government coal purchases introduced during the year. It is reported that this chemical control has resulted in considerable monetary savings since it was introduced.
Water Supplies.
Of the 1348 samples of water examined during the year, 240 were samples of filtered and unfiltered wated taken at the filter plants, and the remaining 1108 were from taps in houses from all parts of Hongkong and Kowloon. In addition to these 24 samples of sewage effluents were examined.
Complaints of a chlorine taste in certain supplies having been made, experiments were made in the Laboratory to ascer tain the concentration of chlorine necessary to cause a percepti- ble taste. It was found that 0.3 parts per million could be detected in the cold and 0.2 paris if the water were heated. Concentrations of C.1 per million and under appeared to be undetectable by taste or odour.
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