New South Wales.—Much depends upon what temperature is deemed a "high level." If we assume that 90 degrees and upwards is a high level, then such periods are very rare in Sydney; in fact during the past 24 years there have only been three. In 1868 there were three consecutive hot days of which the mean temperature was 91.8 degrees; in 1870 a period of four days with a mean temperature of 91.3 degrees; and in 1874 a period of four days with a mean temperature of 90.2 degrees. Since then, although sometimes near it, the temperature has never been for three days over 90 degrees. Taking a lower level, we have one period of nine days in 1870, the longest on record, during which the mean temperature was 82.6 degrees. It must, however, be distinctly understood that what is here taken is not the mean temperature of each 24 hours, but the highest temperature reached during the day, and which would not as a rule last more than three or four hours, if so much. If the mean temperature of the day were taken these temperatures, as given, would have to be reduced at least 10 per cent.
Victoria.—It is very unusual to have a hot period lasting more than three days; when it does happen it is generally in February or March. In the majority of cases high temperatures (over 90 degrees) do not last more than one or two days. The exceptions generally occur in February or March, and have sometimes extended to four or five days hot weather, with a temperature of over 80 degrees with a maximum of about 90 degrees, has on a few occasions during the last 30 years extended from five to ten days; and in 1890, a memorable instance, to 12 days (the only case for 37 years).
South Australia.—The longest stretch of continuous heat noted was in January and February 1857. On January 28th, 29th, and 30th, the temperature exceeded 100 degrees, and during the whole of February it was over 90 degrees on 25 days, and above 100 degrees on 12 days, the mean being 107 degrees. In January 1858 there were 10 consecutive days over 90 degrees, of which eight consecutive days were over 100 degrees. In January 1860 there were in the beginning of the month seven consecutive days, above 100 degrees (maximum 107.5 degrees). In the middle of the same month, seven days were over 90 degrees, of which five exceeded 100 degrees, two days reaching 113.7 degrees. These are, however, exceptions to our usual experience. Although there are several other instances of great heat, yet the foregoing will suffice to show what we occasionally suffer without much harm being done.
Queensland.—During the period February 17th to February 23rd, 1891, the shade temperature at Townsville ranged between 81 degrees and 62 degrees, but at Cairns a range between 82 degrees and 70 degrees is of frequent occurrence, within at least fortnightly periods.
ANY INFORMATION WITH REGARD TO HUMIDITY OF THE ATMOSPHERE ALSO, WILL BE OF GREAT VALUE. ALL PHYSICIANS ARE OF OPINION THAT A HIGH TEMPERATURE, COMBINED WITH MOISTURE, IS VERY IRRITATING TO THE LUNGS OF THOSE AFFECTED WITH PULMONARY DISEASE.
Before setting forth the different answers in response to this, it will be desirable to refer briefly to the term "humidity." The humidity of the atmosphere is defined as the degree of its approach to saturation. Air completely saturated is represented by 100, and that absolutely free of vapour by 0. As a matter of fact, however, the latter never occurs; even in the driest regions of Arabia a humidity of 10 per cent. is almost unknown. For its estimation the Wet and Dry Bulb thermometers are employed. These consist of two ordinary thermometers. One has its bulb exposed so as to register the temperature of the air. The bulb of the other is covered with muslin; this latter material being kept wet through its connection with a cotton wick dipping into a vessel of water. The water ascends from this vessel by capillary attraction, spreads over the muslin, and evaporates quickly or slowly, according to the dryness or moistness of the atmosphere. Thus when the air is driest the difference between the two thermometers will be greatest, and, on the contrary, when it is completely saturated with moisture the two readings will be almost identical.
New South Wales.—A considerable part of the colony, forming the western plains, is subject to great heat, caused, no doubt, by the sun's great power on treeless plains, and the almost total absence of cooling winds; yet, although in summer the temperature here frequently rises over 100 degrees, and sometimes up to 120 degrees, owing to the cold at night and in winter the mean temperatures are not greater than those of corresponding latitudes in the northern hemisphere. This region of the colony is remarkably dry, and stock of all kinds thrive well and are very free from disease. At Bourke, the driest place in the colony, the humidity for a long series of years is—in the spring 51 degrees, in the summer 49 degrees, in the autumn 61 degrees, and in the winter 74 degrees. At Sydney the humidity in the Spring is 69 degrees, in the summer 70 degrees, in the autumn 79 degrees, and in the winter 79 degrees.
Victoria.—The humidity of the air of Melbourne is low, the average being 71 per cent. In the summer it falls to 65, and on hot days is generally very low. The characteristic of our hot weather is that it is usually extremely dry; the exceptions are very few, and occur in the late Spring and early autumn during thundery, muggy weather. On the hottest days, with north winds, the dryness makes the heat much more endurable, and the humidity frequently falls to between 30 and 40 per cent.
South Australia.—Attention has already been drawn to the fact that the hot, dry air met with on the Adelaide plains is far more endurable than a lower temperature in which the atmosphere is surcharged with aqueous vapour. A damp atmosphere is a rare thing in South Australia during the summer, though in March there are at times some warm and humid days. In the winter the air for the most part is dry, although the nights are often damp. The Mount Lofty Ranges, close to Adelaide, afford a cool retreat; they have a very large rainfall, in some years over 50 inches. The climate at Mount Gambier, in the south-eastern part of the colony, is cooler and damper; it has also a much heavier rainfall than the Adelaide plains.