lO 



SCIENCE. 



[Vol. XVIII. No 439 



other migratory locusts, as well as to the non-migratory species. 

 Detailed descriptions of the various machines which were given 

 in the original reports are, for the most part, omitted, in the belief 

 that the figures themselves vrill be sufficiently suggestive for the 

 purpose. In point of fact, many of these machines, especially the 

 more complicated, while serviceable, cannot be recommended to 

 the average farmer dealing with the locust plague, and experience 

 has shown that those simple forms providing for the use of coal- 

 oil and coal-tar are, on the whole, the most efficacious against the 

 unfledged insects. It is, therefore, to this portion of the bulletin 

 that Professor Riley particularly calls the attention of those need- 

 ing the information contained in it. But little experience of 

 practical value has been had since the last great invasion; hence 

 little has been added to tliis section of the bulletin beyond a brief 

 description of the trapping system used in Cyprus against the 

 migratory locusts of the Old World, and an account of the bran- 

 aisenic mash remedy used in California in 1885 against the devas- 

 tating locust. 



THE TREES OF TASMANIA. 



The government of Tasmania has recently issued a publication, 

 the " Tasmanian Official Record," which contains much useful and 

 interesting information concerning the trees of that island. It is 

 peculiarly a forest country, and many of the trees are of great 

 dimensions, towering over and eclipsing the lesser undergrowths 

 on plains, valleys, hills, and mountain slopes. Of the 16,778,000 

 acres comprising the total area, there are only 75,000 acres occu- 

 pied by lakes, and 488,354: acres of cultivated land only partially 

 cleared of its timber. With the exception of minor areas on the 

 tops of mountains or among the barren uplands of the western 

 highlands, the whole of the rest of the country is occupied with 

 an almost continuous virgin forest, mainly composed of the vari- 

 ous forms of eucalypti (gum trees), one noted example of which, 

 the lolosa blue gum, has been recorded as measuring 330 feet 

 high. Many of these trees have stems measuring 150 feet high 

 without a branch, with a girth of about 40 feet towards the base; 

 and it is also recorded that a blue gum at Southport (Eucalyptus 

 globulus), the prevailing tree towards the south of the island, 

 " contained as much timber as would fully suffice to build a 90- 

 ton schooner." 



With such a wealth of forest trees, Tasmania's sources of timber 

 supply must be infinitely great, and in the near future must be of 

 great industrial value ; but the difficulties of transit, the ignorance 

 of their economic value in distant markets, the plethora of local 

 supply, and tbe necessity for clearing the land in the most conve- 

 nient way, all tend, it is said, to produce waste and improvidence 

 in respect of timber products, which might soon become a great 

 source of national wealth. 



The necessity for the better conservation of the natural forests 

 in Tasmania has lately commanded the attention of the local gov- 

 ernment, and a department has been created for the purpose of 

 establishing conserved areas, and for regulating all matters con- 

 nected with the cutting of timber on government lands. 



The following is a description of the more important timbers as 

 regards their industrial value. The blue gum has its home prin- 

 cipally in the southern parts of Tasmania, where it attains great 

 dimensions. Many of these trees exceed a height of 280 feet, with 

 a girth of from 40 to 50 feet. A tree called "Lady Franklin's 

 tree," near Hobart, is stated to have a circumference of 107 feet 

 at a height of four feet from the ground. The timber of the blue 

 gum is of rather a pale color, hard, heavy, strong, and durable. 

 In transverse strain its strength is about equal to English oak. It 

 is used in house and ship building, and also by carriage builders 

 and manufacturers of tools. 



The " peppermint tree" has a wide range, as it is found in the 

 southern and eastern humid districts of Victoria and New South 

 Wales, as well as in Tasmania. It varies greatly with altitude, 

 climate, and soil, and is found at all heights up to 4,000 feet ele- 

 vation. In the poorer lands the trees, though tall, are not re- 

 markably so, but in the deep wooded gullies and in the moist 

 ravines of mountains it attains such remarkable dimensions that 

 it has obtained the distinction of the " giant eucalyptus" of Aus- 



tralia. The timber of this tree is useful for many kinds of car- 

 penters' work, as in drying it does not split. It is also used in 

 shlp-buUding, for keelsons and planking. Besides its timber, this 

 tree is famous for other products of value. The ashes of the foli- 

 age yield, it is stated, ten per cent pearlash; and from one thou- 

 sand pounds of fresh leaves, with their small stalks and branches, 

 the yield of eucalyptus oil by far surpasses all that of other con- 

 geners, amounting to five hundred ounces per thousand pounds. 



The stringy-bark gum is a valuable tree, found in abundance in 

 Victoria, South Australia, and Tasmania. It is straight stemmed 

 and of rapid growth, attaining a maximum height of 300 feet. 

 The wood of this tree supplies a large portion of the ordinary sawn 

 hard timber for rough building purposes. It is also well adapted 

 for carriage, cart, and wagon building, wheelwork, and agricul- 

 tural machinery, as well as for the framing of railway carriages 

 and trucks. The white gum, or "manna tree," is abundantly 

 distributed throughout the island, and has also a wide distribution 

 on the mainland of Australia. Its timber is used for shingles, 

 rails, and for rough building materials. The small branching 

 trees on open ridges and plains are noted for exuding a sugary 

 substance called " manna," which is esteemed a great luxury, and 

 is eagerly sought for by the young. 



The gum-topped stringy bark Is held in high esteem in Tas- 

 mania, and the chief peculiarity of this tree is that, while the 

 lower part of the butt is clothed with a thick fibrous bark, the 

 upper part and the smaller limbs and branches are quite smooth. 

 The timber from this tree is highly prized, and it is described by 

 competent authorities as second only to the blue gum. The iron 

 bark is a valuable tree attaining a height of 150 feet. The trunk 

 is sawn into good timber, and it is also used for posts and rails. 



One of the most handsome of the native trees is the blackwood, 

 which is widely distributed along the slopes of the north-west 

 coast. It attains a height of from 60 to 130 feet. The timber is of 

 a brovsTiish color, closely striped with streaks of various shades 

 of a reddish brown. The more ornamental logs of this wood are 

 exceedingly beautiful, and fetch a high price. The myrtle or 

 beech is common in Tasmania, and forms a large proportion of the 

 forests. The "huon" pine is said to be the grandest and most 

 useful of all the soft woods. It is abundant along the rivers of the 

 south-western parts of the island, attaining a height of from 60 to 

 120 feet, with a diameter of three to eight feet. Its timber is almost 

 indestructible in any situation. It is largely employed, locally, for 

 all kinds of furniture and ornamental work, and is the most highly- 

 esteemed of all kinds of wood for the lighter sea craft. Among 

 the other trees of Tasmania may be mentioned the red pine, oyster 

 bay pine, silver wattle, black wattle, and native cherry. 



LETTERS TO THE EDITOR. 

 Grcwth of the Face. 



DuEiNG the past year investigations upon the physical growth 

 of children have been conducted in the Worcester schools. The 

 preliminary tables on the growth of the female face bring out 

 some facts of considerable Interest. There seem to be three dis- 

 tinct periods, the first ending about the seventh year, and the 

 third beginning about the fifteenth year. A striking peculiarity 

 is the seemingly abrupt transition from the types of one period to 

 those of the succeeding. The sudden disappearance of the lower 

 widths of face, and the equally sudden appearance of the types of 

 the succeeding period, e.g., the sudden shooting up of the widths 

 to almost adult dimensions at about the age of eight or nine offset 

 by the equally sudden disappearance of the distinctively childish 

 characteristics at the age of eleven. These peculiarities also ap- 

 pear at the ages of twelve and fourteen respectively in the suc- 

 ceeding period. This would seem to indicate the very slow growth 

 of some children until the ages of about eight and fourteen re- 

 spectively are reached, and then a very rapid development of each 

 individual to her proper position in the series. This Axel Key 

 found also to be true with respect to the total height of the Swedish 

 children observed by him. 



In the second period very many of the forms are already adult, 

 and, if not at their fullest development, have very nearly ap- 



