424 



NATURE 



[Ski'TK-mbkr 3, 1896 



or Aira cirspilosa, Linn.)- This species is locally known in 

 England as tussocU grass, and as " bull faces " or" bull pates," 

 and efforts are constantly made to extirpate it from our per- 

 manent pastures. In Australia, however, " it affords a fair 

 pasturage if periodically burnt down." (Iraziers on and near 

 the Australian Alps have been asked to send notes of their 

 observations of this species, as it is regarded as quite possible 

 that the Australian plants differ in forage value from those of 

 Ihc northern hemisphere. The culms are sufficiently tough 

 to permit of door-mats being made from the hay. 



What is known as the " shade-tree insect problem," in the 

 Eastern United States, forms the subject of an illustrated bulletin 

 of the Department of Agriculture at Washington. The great 

 abundance of insects which attack shade-trees was a noteworthy 

 feature in many of the cities in the summer of 1895. In almost 

 every low-lying town from Charlotte, N.C. , north to Albany, 

 N.Y., the elm-leaf beetle Galcrticella biteola defoliated the 

 English elms, and often the American elms. The bagworm 

 ( Thyridofteryx ephoiterifforiiiis)^ the white-marked tussock 

 moth (Orgyia kitcostigina)), and the fall webworm (Hyphaii- 

 Iria cuiiea) are conspicuous amongst the depredators. Some 

 species of trees suffer much more than others, the beeches, 

 hornbeams, and alders appearing to have few insect enemies. 

 Spraying and banding of trees and other checks are being em- 

 ]iloyed, and one of the Washington newspapers has advocated 

 the formation of a tree protection league amongst the citizens. 



A CORRESPONDENT in the Grahamstown Journal tells how 

 he cleared his garden of a pest of locusts. A number of dis- 

 eased insects were obtained and ground into a fine powder, 

 which was then placed in a bucket of water. Some of the 

 mixture was poured on a few locusts of a fairly good-sized 

 swarm, and before many days had elapsed numbers of the 

 locusts w'ere found dead, and eventually the garden was quite 

 clear of the pest. 



On account of the great success of the botanical models made 

 by the firm, Herrn. R. Brendel, in Berlin, the same firm is now 

 constructing zoological models out of papier-mache, some of 

 which are exhibited in the Berlin Exhibition this summer. For 

 instance, there is a model of the ordinary house-fly (Musca 

 doincstica) thirty times life-size ; it is very accurately made, and 

 all its parts are beautifully worked and distinct, making it un- 

 necessary to take it to pieces. By means of a small piece of 

 mechanism the spreading of the wings can be demonstrated. 

 There is also exhibited, in a series of eight models, a plaster 

 representation of the development of the frog, each being ten 

 limes life-size ; they are all so arranged that they can be lifted 

 off their supports and examined more minutely. With the help 

 of such useful models as these, students of zoology will be more 

 easily able to grasp some points which cannot always be ob- 

 tained from pictures or diagrams. These models should also be 

 found most useful in schools where the pupils do not often come 

 in contact with museums. 



In Italy, almost the only instruments used for the study of 

 earthquake-pulsations are long and heavy pendulums. The 

 greater the length the more steady is the bob during movements 

 of the ground, and the heavier the bob the more readily is the 

 friction of the recfirding pens overcome. In the last number of 

 the BoHcttiiio of the Italian Seismological Society (vol. ii. , 1S96, 

 pp. 62-65), Dr. A. Cancani describes the latest form of seisnio- 

 metrograph constructed under his superintendence. Two instru- 

 ments have been made, one for the geodynamic observatory at 

 Kocca di Papa, and the other for that at Catania. The former 

 is 15 metres long and 200 kg. in mass, the latter is 26 metres in 

 length and has a mass of 300 kg. ; in other respects they are 

 almost identical. The suspending wire of the pendulum passes 

 NO. 1 40 I, VOL. 54] 



at its lower end through slits in the short arms of two horizontal 

 levers. The slits are at right angles to one another, but the levers 

 are bent at an angle of 45° in opposite directions, so that the 

 pens at the free ends of the long arms write their component 

 records side by side on the same moving band of paper. The 

 paper is driven at the rate of 60 cm. an hour, a velocity great 

 enough to allow the individual undulations to be examined, and 

 the times of the different phases to be determined with consider- 

 able accuracy. 



The restlessness or alarm shown by birds and animals before 

 the occurrence of an earthquake sensible to man is now well 

 known, and is probably due to the very small tremors which 

 precede the larger vibrations. In an interesting paper {Boll. 

 Soc. Sismol. IlaL, ii., 1896, pp. 66-74), Dr. A. Cancani has 

 collected a large number of examples observed in Italy. He 

 points out besides the important fact that, while most animals 

 are disturbed during and after an earthquake, it is only at some 

 distance from the epicentre that they exhibit any signs before 

 the shock is perceptible to man. The explanation Dr. Cancani 

 gives is that the tremors move with a greater velocity than the 

 large vibrations, but that a considerable space must be traversed 

 before they have outraced the latter by several seconds. 



In the Btilklin of the Constantinople Observatory for 

 January 1S96, Dr. Agamennone concludes his summary of the 

 earthquakes felt in Turkey during the year 1895 (see Nature, 

 vol. liv. p. 373). The number of recorded shocks amounts to 

 400, and these are found to belong to thirty-one seismic centres, 

 the principal of which are near Paramythia, Imam Keuy 

 (Aidin), and Pergama. In the neighbourhood of Constantinople 

 at least ten earthquakes had their origin, showing that the 

 seismic activity provoked by the great shock of July 1894 has 

 not yet ceased. 



We have received from Prof. G. Vicentini a new and valuable 

 contribution to our knowledge of earthquake-pulsations, con- 

 sisting of a list of the disturbances registered by his two-com- 

 ponent microseismograph at Padua from p'ebruary to September 

 1S95. Many of these can be referred to known shocks, occur- 

 ring either in Italy or in neighbouring countries. On three 

 occasions (March 6, June 15, and July 5) the origin of the 

 pulsations is unknown, but the diagrams are similar to those 

 that are produced by earthquakes taking place at a very great 

 distance. Copies of the diagrams corresponding to twenty-two 

 earthquakes are reproduced on a scale two-thirds of the 

 original. 



In the current number of the Joitrnai of the Anthropological 

 Institute of Great Britain and Ireland (vol. xxvi. No. l) Mr. 

 Robert M. W. Swan gives some very interesting notes on ruined 

 temples in Mashonaland, These temples are of the Zimbabwe 

 style ; i.e. they seem to take the form of circular arcs, if not 

 complete circles. Practically only one he describes — that of the 

 temple at Lundi River — attains to anything like a circular shape, 

 and this is very complete, being only pierced by two openings. 

 The others scarcely reach 180°, and these seem always to be 

 pierced by a doorway. The temple at Lundi River stands on a 

 little knoll about half a mile south of the waggon road, and 300 

 yards towards the east of the river. It is built of small rectangular, 

 naturally-shaped blocks of granite, laid in very regular level 

 courses. Erom the fact that the inside finely-built wall supports, 

 to some extent, many of the stones of the outside wall, it is sug- 

 gested that it is probable both were built at the same time. Mr. 

 Swan took measurements of the different parts of the building. 

 The circumference of the temple w.as 169 feet 61 inches, or 

 I7'I7 feet x ir- (10 cubits x tt-). At no point did the founda- 

 tions of the temple diverge more than a few inches from a true 

 circle. The two doorways into the building were 60 feet 8J 



