November 15, 1894] 



NA TURE 



6s 



More than half the area of the State forests is already under 



the high- forest treatment, and consists chiefly of highly-pro- 

 ductive silver-fir and beech forest in the Vosges ; forests of 

 finui Laricio and Fittus Pinaster in Corsica, which only yield 

 poor returns on account of the frequency of forest fires ; beech 

 forests in Normandy with a small proportion of oak, and ex- 

 tensive oak forests on the Loire and its tributaries, where beech 

 is kept subservient to the principal species. The maritime 

 pine forests of the Landes and Gironde yield large quantities 

 of resin and turpentine, as well as inferior timber, pit-props, &c. 

 The communal forests are distributed as follows : — 



Percentage 

 of area. 



Simple coppice >4'7 



Coppice-with-standards ... 53'^ 



,, under conversion to high-forest ... I "o 

 High-forests 311 



The communal simple coppice areas chiefly supply fuel to 

 villagers, and consist mainly of Qiierciis Ilex in the south, and of 

 common oak and other species in the Ardennes and lower 

 slopes of the Alps, near the villages and below the coniferous 

 forests of the higher zones. 



Coppice with-standards is the commonest mode of manage- 

 ment of communal forests, and is distributed chiefly in the 

 temperate regions of hills and plains of the north-east of 

 France, and little of this area is being converted to high-forest, 

 as the people do not care sufficiently for the benefit of futurity to 

 sacrifice a considerable part of their present revenues. 



The high forests belonging to communes, &c. , are chiefly 

 situated in the Vosges, Jura, .\lps, Pyrenees, and in Corsica, 

 consisting chiefly of conifers mixed with beech. 



Detailed tables are given regarding the yield of the forests in 

 material and money. 



Thus the production of the forests during the year 1892 was 

 as follows : — 



The average annual production per acre of the wooded area 

 of the forests is as follows ; — 



c. feet. s. d. 



State forests ... ... ... 43.^ ... 9 5 



Communal and other forests... 37 ... 5 10 



It is evident that the State forests yield more wood, and of a 

 better quality, than the communal forests. 



Leaving out the Departments of the Seine and Corrcze, where 

 the production in quantity of material and money is abnormally 

 high, the areas of State forests in these Departments being in- 

 considerable, the forests of the Vosges head the list with an 

 annual yield of 7'I36 cm. per hectare, equivalent to loi c. feet 

 ^ler acre, and worth £\ y. 4^. 



This reiurn is exceeded in value, though not in quantity, 

 by the forests of the Doubs, «here there is much oak grown as 

 well as silver-fir, and the yield i.s 5'867 c. metres per hectare 

 = 84 c. feet per acre, and worth £1 Ts. ^d. an acre. 



The productiveness in different classes of material of the 

 <lifferent lorests are as follows : — 



Timber 



CoHifers. 



Exceeding 20 in. in diameter .. ... 94 



Less than ,, ... ... 5'3 



Poles 06 



Firewood ... ... ... ... ... -.. 7'7 



The proportions of the yield of broad-leaved and coniferous 

 timber is as follows : — 



Percentage. 



Broad -leaved... ... ... 77 



Coniferous .. ... 23 



It is noted that the broad-leaved species yield 74 per cent, of 

 firewood, while the conifers only yield 33 per cent. 



In the communal and other forests the production is as 

 follows : — 



Percentage. 



Broad-leaved ... Sl'3 



Coniferous... ... ... ... .. ... 187 



And the percentage of firewood in the former case is 86 per 

 cent., whilst for the coniferous forests it is 25 per cent. These 

 forests are less productive in timber, and especially in timber 

 exceeding 20 inches in diameter, than the State forests, which 

 accounts for their reduced money reiurn. 



If we omit the large sum of ;{^g9, 300 spent in 1892 on planting- 

 up dangerous mountain sides and regulating the beds of 

 mountain torrents, and £?i,^oo spent on fixing shifting 

 sands, the cost of maintenance of the whole of the productive 

 forests referred to in 1892 was ;^397,o8o, or about Ij. 2d. 

 per acre, which must therefore be deducted from the yield 

 of the forests to determine their net revenues per acre. 



The following is a complete statement of the French forest 

 charges for 1892 : — 



Establishment... ... ... 231,800 



Forest schools 6,SSo 



Works of improvement in the forests ... 58,000 



Mountain reboisenunt ... ... ... 99,300 



Fixing shifting sands ... .. ... ... 8,400 



Working plans and fellings ... ... ... 16,000 



Management of (ha:ses which are not leased 2,000 



Taxes ... ... ... ... ... ... 72,400 



Law and other charges ... 10,000 



;£ 504. 780 



Of this amount £s,\,2(>%, or about 2d. an acre, is refunded to 

 the State by the communes and public estahlishments for the 

 management of their property. W. R. Fisher. 



State Forests. 

 Broad-leaved Species. 



( Oak 20 in. in diameter and above 

 Timber •; Do. less diameter 



( Other broad-leaved species ... 

 Poles 

 Firewood ... 



NO. 



1307, VOL. 51] 



Percentage of 



yield. 



• ■ s 

 s 

 61 



.. 3-8 

 ■■ 57-1 



THE PROPERTIES OF LIOUID ETHANE 

 AND PROPANE. 



A COMPREHENSIVE study of the properties of these 

 ■^ primary hydrocarbons in the liquefied condition has been 

 made by Dr. Hainlen in the laboratory of Prof. Lothar Meyer 

 at Tubingen, and an account of his work will be found in the 

 current issue of Liebi'o's .Annalin. Owing to the greater 

 ease with which it undergoes liquefaction, propane was first 

 investigated. The hydrocarbon was obtained in a slate of 

 purity by means of the admirable method of preparation dis- 

 covered in the same laboratory in the year 1883 by Kohnlein, 

 which consists in heating propyl iodide with aluminium chloride 

 in a sealed tube to 130°. .\fter subjection to this temperature 

 for twenty hours the tube was allowed to cool, and subsequently 

 placed in a freezing mixture ; while immersed in the latter it 

 was found practicable to open it without danger or loss, the 

 accumulated gas being readily transferred to a gasholder over 

 w.'tter. 



In order to determine the boiling-point of propane, the 

 purified gas was first condensed to the liquid state in a U-tube 

 surrounded by solid carbon-dioxide. It was then transferred 

 to the special boiling-point apparatus by evaporation and re- 

 condensation, the last traces of impurities being eliminated by 

 this process of repeated distillation. The special apparatus 

 consisted of a glass tube closed at the lower end, furnished 

 with a side tube for the entrance of the gas, and with a stopper 

 at the open end perforated for the passage of an exit-lube and 

 a thermometer. The upper h.ilf of the cylinder was surrounded 

 by solid carbon-dioxide, and the lower portion was protected 

 by a mantle of badly-conducting felt. Upon the entrance of 



