M 69
The routine examinations of the water filtered through the new Pattison mechanical filters at Bowen Road showed the product to be highly satisfactory, the highest value for "oxygen absorbed" being 0.023, for free ammonia, 0.0028 and for albumenoid ammonia, 0.0061, all expressed in parts per 100,000. As regards the physical properties of this supply, the colour of the filtered water was never higher than 2.5 Lovibond colour units, and the transparency was throughout, 100 cms.
With regard to the water from the other filtration plants it may be said that over 95% of the samples examined were completely satisfactory. The highest value for albumenoid ammonia obtained was that given by the Shaukiwan supply in May, namely 0.011 parts per 100,000, this supply during the same month also giving the highest value for free ammonia, namely 0.0082 parts per 100,000. The highest values for "oxygen absorbed" were yielded by the Aberdeen supply, and the West Point supply, in May, namely 0.055 per 100,000. The Aberdeen supply in May gave colour and transparency figures of 15 Lovibond units and 15 cms. respectively, but these figures were quite exceptional. The great majority of the samples examined gave values for colour less than 15 Lovibond units and transparency figures above 80 cms.
The hydrogen ion concentration was determined on all samples from the main supplies, both on the raw and on the filtered waters, and much useful data was thus obtained as to the reaction of the local raw water. These values might be of considerable importance in any projected malaria campaign.
The staff supervising the Pattison plant at Bowen Road are now equipped to carry out routine determinations of the hydrogen ion concentration of the water for control purposes on the spot.
The electrical conductivity method has been used throughout the year on all water from the public supplies, both filtered and unfiltered.
Original Work.
A bomb found by the Police was submitted for examination. It was found to consist of a tin canister containing three sticks of dynamite packed round with earth and stones. The sticks of dynamite were fitted with fuses and detonators.
One "knock-out" pistol and two cartridges were submitted for examination. Such pistols are designed to stupify the person fired at, without producing serious bodily harm. The cartridges were found to contain a small charge of black powder together with a gelatin capsule of allyl isothiocyanate. Unless the person fired at was within ten feet the effect of the pistol would be almost negligible.