M(1)45
In view of the fact that highly coloured sweets and cakes were found on sale in Shanghai which on examination were found to be coloured with ordinary poisonous paint pigments, samples of coloured sweets and cakes were purchased at a number of Chinese shops in Hong Kong and Kowloon and examined at the Laboratory. No really harmful pigments were found, the colouring matters present being either vegetable colours or harmless aniline dyes free from arsenic and other dangerous contaminating substances.
The sample of flour reported as unfit for human consumption was found to be dirty and infested with the common meal mite, (Acarus farinae) to the extent of 100 per grain of flour or 43,200 per oz. Small maggots were also present.
All the samples of commercial sugar examined were tested by the electrical conductivity method in addition to the ordinary determinations; the former proving to be a very sensitive method for detecting foreign inorganic soluble substances. In one case the presence of 0.08% of common salt in the sugar caused a rise in the electrical conductivity of over 550 reciprocal megohms.
A more sensitive method was introduced during the year for detecting traces of carbon bisulphide in flour which had been treated with the vapour of this substance for insecticidal purposes. This was in connection with the treatment of naval stores at the Kowloon depot.
MINERALOGICAL ANALYSES.
The 139 samples of metals and ores examined during the year comprised the following:-
Metals 1927 1926 Tin... Antimony Alloys Lead Ores 1927 1926 Wolfram 30 34 Manganese ore 28 4 Bismuthite 4 6 Antimony ore.. 2 12 Tin ore 0 2 Galena 0 1 Gold ore 1 0 Total 66 73 126 87The table has been reconstructed for better readability.
was removed as per rule 12. The original table data was preserved and formatted according to rule 14. Other corrections were made according to the given rules, such as fixing spelling errors (e.g., "commerical" to "commercial", "consump-tion" to "consumption"), spacing issues, and rejoining broken sentences. The file reference "M(1)45" was formatted according to rule 10.