648 



NATURE 



[February 12, 1920 



similar, but contained an amplifying valve and a 

 telephone. Messages could easily be sent in this 

 way. This method proved of great value when the 

 ordinary lines were cut by the enemy. The valves 

 also made "direction finding" and communication 

 between aeroplanes easy. When used as generators 

 they give currents the frequencies of which can be 

 varied from a tenth to millions per second. They 

 are of great value, therefore, for calibrating wave- 

 meters. It is also possible by their use to maintain 

 the oscillations of mechanical vibrators bv suitable 

 arrangements. They introduce the equivalent of 

 negative friction or negative damping into the circuits. 



THE FUTURE OF TROPICAL AUSTRALIA. 



'X'HE possibilities of settlement in tropical Australia 

 ■•■ are discussed in great detail by Mr. GrifVith 

 Taylor in the Geographical Review for \ugust(vo\.v\i\., 

 No. 2). Taking tropical Australia to be bounded bv the 

 southern tropic, Mr. Taylor gives it an area equal to 

 barely 40 per cent, of the total area of Australia and 

 about one-thirtieth of the total population. Analysing 

 carefully the climatic and vegetational factors, he con- 

 cludes that it is mainly a pastoral land except in 

 eastern Queensland, where tropical crops and wheat 

 do well. The coastal lands of the Gulf of Carpentaria 

 are also fit for agriculture. Mr. Taylor sees little hope 

 of tropical .Australia becoming a pro.sperous and pro- 

 ductive land if the White .Australia policy is main- 

 tained. Chinese are chiefly restricted to tropical lands 

 with an abundant rainfall. The hot, dry climate of 

 the greater part of tropical Australia is best suited to 

 the natives of India. JEven if white settlement proved 

 to be possible by a slow process of acclimatisation, it 

 would only be at the cost of many lives, and at best 

 would take a very long time. But, assuming that 

 political difficulties will eventually be overcome, Mr. 

 Taylor tries to estimate the future population that 

 tropical Australia could support provided transport 

 facilities are introduced. One district in the interior 

 of Western Australia and the Northern Territory, with 

 an area of about 150,000 square miles, is suited for 

 any population. The remainder of the area under 

 consideration, according to his estimate, couki sup- 

 port a total population of about 1,400,000, with a 

 density varying from 8 per square mile in the east 

 of Queensland to i per square mile or less in the 

 more arid parts of Western Australia and the inland 

 regions of the Northern Territory. Mr. Taylor's paper 

 is a valuable contribution to the study of Australian 

 problems. 



PLANT-LICE IN THE TROPICS. 



A RECENT publication of the Scientific Institute of 

 ^*- Buitenzorg contains a well-worked-out monograph 

 by P. Van der Goot of the aphides of Java. The author 

 attributes the comparative scarcity of plant-lice in the 

 tropics, as compared with temperate regions, to the 

 attacks of insect enemies such as Syrphidae, Coccinel- 

 lidae, and mining wasps, and also to the occurrence 

 of violent rainstorms, drought, and other unfavourable 

 climatic conditions. The tobacco plant and sugar-cane 

 are the only cultivated plants seriously injured by 

 aphides in Java. In Europe there is always a longer 

 or shorter period of lowered temperature during which 

 the functions of plants are more or less in alievance. 

 This unfavourable period is generally passed through 

 by aphides in the form of eggs laid in autumn by 

 sexually developed females. If, however, the tempera- 

 ture is artificially kept up, the sexually developed 

 females persist, together with the eggs, and propaga- 

 tion takes place in the regular manner, i.e. bv means 



NO. 2624, VOL. 104] 



of parthenogenetic, viviparous females. In the troi)ics 

 there is no considerable lowering of temperature ; there 

 is, however, generally a rainy and a dry season. In 

 the latter, though there is often a failure of nutri- 

 ment, there is never found a rest-form in the condi- 

 tion of sexually produced eggs. Even in mountain 

 regions, where in the dry season the temperature mav 

 fall to freezing point, the author has never found 

 sexually developed aphides. Propagation of these 

 insects in the tropics, says Van der Goot, takes place 

 invariably by means of parthenogenesis. He has never 

 observed in Java a regular migration of aphides ; 

 whether such a phenomenon ever occurs he is unable 

 to conjecture. The production of winged forms does 

 not always depend on the drying-up of plant-food, for 

 some species acquire wings in the middle, and others 

 at the end, of the dry season. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Birmingham. — The board of management of the 

 Brewing School has ^iven the sum of 20,000/. for the 

 endowment of a chair of brewing, to be known as 

 the Adrian Brown chair, in memory of the late Prof. 

 Adrian Brown, F.R.S., the first professor of brewing 

 in the University. 



A sum of more than 2000Z. has been subscribed for 

 the endowment of a lectureship in social philosophy 

 as a permanent memorial in honour of Prof. J. H. 

 Muirhead. 



Li\KRpoor.. — ^The council of the University has 

 appointed Mr. G. E. Scholes to the recently estab- 

 lished chair of engineering-thermodynamics of heat 

 engines. Mr. Scholes studied in the engineering 

 department of Owens College, Manchester, and has 

 held important teaching posts in engineering subjects 

 at .Manchester and Liverpool Universities and in the 

 Army engineering schools. Durintj his career in the 

 .Army, which he joined in 1915, Mr. Scholes did valu- 

 able work as a captain-instructor in petrol and other 

 engines at one of the R.E. schools. .Mso as experi- 

 mental ofliccr he successfully devised imoortant tech- 

 nical improvements relating to aircraft defence. The 

 chief of these w-as a device in connection with soimd- 

 locators, which Mr. Scholes designed and constructed. 

 This invention was adopted and standardised, the 

 inventor beinff awarded a grant from the Inventions 

 .Award Committee. 



Makchester. — Mr. Frank Watts, who has been 

 appointed assistant to the director of the Department 

 of Industrial .Administration at the College of Tech- 

 nology, will devote especial attention to a study of 

 vocational selection and trnininsf, and assist in 

 working out a set of tests of industrial fatigue. 



The Regional .Association, the president of which 

 is Prof. Patrick Geddes, will hold a conference on 

 regional survey durinc? the Raster vacation (.Anril 6-1-;) 

 at the Outlook Tower, Edinburfh. Residence is 

 being arranged in l^niversitv Hall, so that the ad- 

 vantages of communal life may be enjoyed during the 

 week. 



The Seale-Hayne Agricultural College at Newton 

 .Abbot, in Devon, commenced last month its first series 

 of regular courses in agriculture with a very s.^tisfac- 

 tory complement of students. The courses given com- 

 prise a three-year diploma in a£<riculture, a two-year 

 certificate in acriculture and horticulture, and short 

 courses uoon various subjects of agricultural import- 

 ance, such as poultry-keening, dairying, etc. 



The election to the Sorbv research fellowshio of 

 the Royal Society and the University of Sheffield will 



