"A NEW FORM OF RAIN-GAUGE."

Daily Southern Cross, Volume XXVII, Issue 4357, 2 August 1871, Page 3

"A NEW FORM OF RAIN-GAUGE."

The following is the paper on this subject read by Archdeacon Williams, before the Auckland Institute, on Monday evening :— " The amount of the annual rainfall, and its distribution over the year, are subjects of more or less interest to a considerable number of people in various parts of the country, and there would probably be more observers in this branch of meteorology were it not for the difficulty experienced in procuring the requisite apparatus, and in replacing accidental breakage. Ordinary rain-gauges appear to be constructed on aome arbitrary scale, a measuring glass being supplied with each, graduated to hundredths of an inch in proportion to the collecting aperture of the instrument. If this glass should be broken the whole apparatus is disabled until another can be procured — a matter involving some difficulty in most cases, as well as a serous interruption to the series of observations. An ordinary chemist's measuring glass cannot be used as a substitute, because an inch of water in the gauge does not correspond to an even number of ounces or drachms. The collecting aperture of the rain-gauge in she Domain is 10 iaches square, therefore me inch of water collected by this instruaent will amount to 100 cubic inchps or 57 705 fluid ounces — a very impracticable quantity to divide into tenths and hundredths. All that is required to make the ordinary otnce glass available for measuring the collected -water is that the collecting aperture of the instrument should be a circle 10^ inches in diameter ; one inch will then be represented by 50 fluid ounces, one-tenth of an inch by 5 ounces, and one-hundredth of an inch by half an ounce. There is * slight error in this, for which, if precision is desired, the necessary correction can b» made. One cubic inch being equivalent to 1 '73296 fluid ounces, the area of she collecting aperture divided by this will gire us the number of fluid ounces contained in one inch of the collected water: thus' 10 52 x 0-7854 -r1'73296 = 49*96666 fluid ounces. The difference between this amount and the assumed 50 ounces is only '0333 fluid ounces, or 16 minims ; a quantity which represents '0007 of an inch, or one-hundredth of an inch in every 15 inches. A funnel of the requisite dimensions can be constructed by any good tinsmith, and a measuring glass, of convenient size, can be obtained at any good chemist's shop. The upper part of the f nnnel should be a cylinder which should be continued downwards for 2 or 3 inches, so as to prevent any water from running down the outside of the instrument into the receptacle below. An empty oil drum, with the top taken out, of a suitable size* to fit under the cylindrical part of the funnel, will serve to aupport the funnel, and to contain a bottle or ether convenient vessel to receive the water. To avoid mistakes, from inadvertence in registering, the amount collected each day should be entered in ounces as well as in hundredths of an inch ; or (which would perhaps be the better plan), a slip of paper may be cemented over the figures on 'the glass-, and the marks numbered on this in Eundredthg of an inch." — A brief discussion ensued after the reading of the paper, during which Mr. Kirk expressed himself strongly in favour of such a form of rain»gauge as* as proposed. The cost of such a gauge as propoted, WQuld UQk be more than * few