234 



SCIENCE. 



[Vol. XII. No. 302 



rens. A sound land-policy, therefore, demands that the nation 

 should give earnest attention to forest management. 



" It has become evident that we are not to escape the conse- 

 quences of disturbing the even distribution of vi^ater-flow by forest 

 devastation, and denudation of mountains and hills, vifhich have 

 been experienced in other parts of the world, and which have 

 reduced fertile lands to barrenness, prosperous communities to 

 poverty. Regard, therefore, for the future welfare of the several 

 communities which in their aggregate represent the nation, calls 

 for a rational forest policy, a proper utilization, a proper distribu- 

 tion, and a proper management of the natural forest. 



" Lastly, if the nation as such is interested in the proper develop- 

 ment of the rich agricultural lands of the plains and prairies, it must 

 be interested also — in that part of its domain, at least — in forest- 

 planting as a means of ameliorating climatic conditions and making 

 the region more habitable." 



Mr. Fernow then proceeds to consider the most immediate needs 

 and the most immediate duty of the general government in regard 

 to the forestry question. " The general government still holds, as 

 an individual, national property, a forest area the extent of which is 

 unknown, but may be estimated between fifty and seventy million 

 acres. The bulk of these lands is to be found on the rugged 

 mountain sides and crests of the Western ranges, notably the 

 Rocky Mountain, Cascade, Sierra Nevada, and Pacific coast ranges, 

 mostly land not fit for agricultural use. The agricultural valleys 

 at the foot of these ranges are not only destitute of timber, but 

 they are dependent for their agricultural productions upon irriga- 

 tion, the water for which is derived from the mountain-streams and 

 more rarely from artesian wells, both of which sources are fed by 

 the rains and snows which fall upon the forest-covered mountain- 

 sides, and gradually find their way to the plain below. It has been 

 proved not only by experience, but by actual experiment on a large 

 scale, that forest cover regulates and beneficially influences the ra- 

 pidity with which these precipitations are carried to the plain for 

 utilization on agricultural lands." 



In order to preserve these woods, a bill has been formulated, 

 which has been submitted to Congress through the agency of the 

 American Forestry Congress. Its essential features are the with- 

 drawal from sale, or other disposal, of all woodlands still in the 

 hands of the government, and the classification of the same into 

 three classes ; the regulation of the sale of timbered land which is 

 fit for agriculture ; and the management of the forests occupying 

 land unfit for agriculture. To insure a proper administration of 

 such a law, to prevent waste and loss by fires, a new bureau in the 

 Department of the Interior is proposed, with a forest commissioner 

 and four assistant commissioners acting as a forestry board. 



" None but such a thorough organization can be expected to 

 guard the national property, of which, under the present neglect, 

 the nation is annually robbed to the extent of from five to ten mil- 

 lion dollars, not counting the damage done by fires and fraudulent 

 operations of speculators. But, as has been stated repeatedly, the 

 forest-cover in the localities in which the bulk of the public timber- 

 lands is situated, notably on the Rocky Mountains and the Pacific 

 slopes, subserve a function which makes its material value of only 

 secondary importance. It has become already evident that the de- 

 nudation of mountain-sides in the region under consideration has 

 impaired the regularity of water-flow, upon which irrigation in the 

 arid valleys below depends. 



" The interest of the nation, therefore, in properly administering 

 this property, reaches beyond that of any material advantage ; and 

 certainly in these mountain forests, in this legislation for their 

 proper administration, lies the immediate national interest in for- 

 estry." 



ELECTRICAL SCIENCE. 



The Heroult Aluminium Process. 



The Swiss Metallurgical Company, established close to the 

 Rhine Fall at Neuhausen, has adopted the process of M. Heroult for 

 the production of alloys of aluminium. The process resembles in 

 some ways that of the Cowles brothers, which is so successfully 

 employed at Lockport in the United States, and which has been re- 

 cently introduced in England and the continent. In both the 



Cowles and Heroult processes an electric current is employed. In< 

 the former it is used simply to produce a very high temperature in- 

 a limited zone, the reduction of the ore being due to the tempera- 

 ture alone and not to any effect of electrolysis, so that an alter- 

 nating could be used as well as a continuous current. In the- 

 Heroult process, according to the views of the inventor, the reduc- 

 tion of the ore is partly electrolytic and partly due to the heat of the 

 arc. The furnace has a carbon pole at the top, and the current 

 passes in by it through the melted aluminium oxide to the reduced 

 metal at the bottom ; the ore is decomposed, the oxygen passing 

 upward and attacking the carbon, while the molecules of the metal, 

 travel downward and are merged in the metal bath. 



The furnace used in the process is a large carbon block hollowed 

 out in the proper shape and enclosed by a frame of iron. In the 

 smaller furnaces a single block of carbon is used and the iron is- 

 cast around it ; for larger sizes slabs of carbon are used, and are 

 held together by wrought-iron bands. There is an opening in the 

 bottom of the furnace for drawing off the reduced metal. The 

 current enters the crucible through a carbon electrode which enters- 

 the top, and which consists of a bundle of carbon slabs, ten feet 

 long, seventeen inches wide, and nine and a half inches deep. The 

 distance of this electrode from the surface of the molten metal is- 

 regulated by an attendant. This distance is very small, preferably, 

 not over a quarter of an inch. One of the electrodes is consumed 

 in producing about half a ton of aluminium. The crucible is cov- 

 ered by carbon slabs insulated from the body of the crucible ; in- 

 the top, holes are provided for the introduction of ore and scrap- 

 metal. The ore generally used is alumina, free from silicon and 

 other impurities, and the scrap metal is either iron or copper, ac- 

 cording to the alloy which is desired. The process of smelting is a 

 continuous one, the ore being introduced and the crucible tapped 

 at regular intervals. The production of aluminium per horse-power 

 hour varies somewhat with the percentage of the metal contained 

 in the alloy, the average being thirty grams of aluminium and the 

 maximum being forty grams. That is, to produce one pound of 

 aluminium requires fifteen horse-power hours on the average, and 

 eleven horse-power hours under favorable conditions. The present 

 capacity of the crucible is four hundredweight of aluminium in- 

 twenty-four hours. 



At the works at Neuhausen the current is produced by two dy- 

 namos driven by a turbine of three hundred horse-power. These 

 dynamos are of the multipolar type, designed by Mr. C. E. L. 

 Brown, and built at the Oerlikon Engineering Works. They are- 

 designed to give six thousand amperes each, at an electromotive 

 force of twenty volts, and they can be worked up to thirty-five 

 volts. The speed of the turbine is controlled by an automatic reg- 

 ulator acting upon a throttle in the inlet-pipe of the turbine. While 

 the working current is normally twelve thousand amperes, it some- 

 times increases to twenty thousand amperes, because of a short- 

 circuit in the furnace, caused usually by one of the slabs of which- 

 the carbon electrode is made burning more slowly than the 

 others and touching the surface of the molten metal. This increase 

 of current does not injuriously affect the dynamos. There is no- 

 sparking at the brushes of the dynamos. The process promises ta 

 be a successful one ; from the figures given it compares favorably 

 with the Cowles process in the amount of aluminium reduced per 

 horse-power. 



An Immense Electric Lighting Station. — In the London. 

 Electrical Revietu is a description of the station of the London 

 Electric Supply Corporation. At the Stowage wharf, Deptford, this 

 corporation is laying down plant sufficient for the supply of 250,00a 

 incandescent lamps, and there is space for three other sets similar 

 to the first, giving a final capacity of one million lamps. The 

 grounds of the corporation have a river frontage, with a wharf for 

 landing fuel and heavy machinery. A fifty-ton derrick has already 

 been erected. The buildings occupy a space of 210 by 195 feet,, 

 and the height will be 100 feet. 



The boiler house is 195 by 70 feet, and is constructed to hold' 

 boilers of 65,000 horse-power, and of these, 13,000 horse-power are- 

 being erected. The boilers will occupy the two lower floors, with- 

 stowage room above for the fuel. The two engine houses are of 

 nearly the same dimensions as the boiler house, and are very mas- 

 sive in construction. In the first of these houses a pair of 3,000 



