516 AUSTEALUN NIGHT TEMPERATURE. 



wards the weather is described as being oppressively hot at mid-day. 

 Then on the 19th March there was a hailstorm at night, and the air 

 was " cold and bracing ; " and so on. Here, then, in a country totally 

 different from the islands of the Mediterranean, where the Grapes are 

 famous for their eicellenee, we have violent variations in temperature 

 between day and night in the month of March, when the Vines are 

 shooting : the air is cold and bracing by night, the sun is grilling 

 by day. 



, It is probable, however, that no one has been prepared for such a fall 

 of temperature by night as is recorded in Sir Thomas Mitchell's late 

 Journal into the interior of tropical Australia. The facts revealed in 

 this interesting work have been fully extracted and made the subject 

 of comment in one of the numbers of the Journal of the Horticultural 

 Society of London, For details the reader is referred to that work. 

 The following is the author's summary of the facts. 



" In the end of April (our October), in latitude 82° S., within 4^° of 

 the tropic, at an insignificant elevation, the thermometer stood at 26° 

 at sunrise, and was as low as 43° at 9 p.m. ; nevertheless, the country 

 produced wild Indigo, Mimosas, Casuarinas, arborescent Myrtleblooms, 

 and Loranths. A degree nearer the tropic in May (our November), the 

 thermometer at sunrise marked 20°, 19°, 18°, 17°, 16°, 12°, and on two 

 separate days, even 11° ! On the 22d of May the river was frozen, and 

 yet herbage was luxuriant, and the country produced Mimosas, 

 Eucalypti, Acacias, the tropical Bottle-tree (Delabechea), a Calandrinia, 

 and even a Loranth. On the 23rd of May the thermometer at sunrise 

 marking 12°, Acacia conferta was coming into flower ; and Eucalypti, 

 with the usual Australian vegetation, were abundant. On the 30th of 

 May, at the elevation of 1118 feet, the almost tropical Delabechea was 

 found growing with the temperature at sunrise 22° and at 9 p.m. 31°, 

 so that it must have been exposed to a night's frost gradually increasing 

 through 12°. And this was evidently the rule during the months of 

 May, June, and July (our November, December, and January) ; in 

 latitude 26° S. among Tristanias, Phebaliums, Zamias, Hoveas, 

 Myoporums, and Acacias, the evening temperature was observed to be 

 29°, 22°, 37°, 29°, 25°, faUiug during the night to 26°, 21°, 12°, 14°, 

 20° ; in latitude 25° S. the tents were frozen into boards at the elevation 

 of 1421 feet, the thermometer, July 5, sunk during the night from 38° 

 to 16°, and there grew Cryptandras, Acacias, Bursarias, Boronias, 

 Stenochiles, and the like. Cymbidium canaliculatum, the only 

 Orchidaceous epiphyte observed, was in flower under a night temperature 

 of 33° and 34°; that by day not exceeding 86°. These facts throw 

 quite a new light upon the nature of Australian vegetation. It may be 

 supposed that so low a temperature must have been accompanied by 

 extreme dryness, and such appears to have been usually the case. 

 Nevertheless, it cannot have been always so, for although Sir Thomas 



