704 



NATURE 



[January 27, 192 1 



that the former maintained a much more uniform 

 output, and usually they improved slightly from day 

 to day untilthey reached their acme on Friday. The 

 relatively unskilled workers, on the other hand, showed 

 a more irregular output, which generally fell off after 

 the second or third working day of the week, and 

 sometimes after the first working day. .Another sec- 

 tion of the report affords striking evidence of the 

 value of rest-pauses. \ firm which desired to increase 

 its output without adding new machinery determined 

 to make the experiment of working the double presses 

 with a team of three girls, each operative working 

 forty minutes in each hour and resting twenty 

 minutes, instead of with two girls working con- 

 nnuously throughout the day. In a short time it was 

 found that the total output from the presses had 

 increased 44 per cent., i.e. the girls were producing 

 individually nearly as much as they had been able 

 to do previously, but in two-thirds the time. 



S. COPY has reached us of the first number (January) 

 of the Journal of Industrial Administration, the official 

 organ of the Institute of Industrial .Administration, 

 which was founded in the spring of last year. The 

 scope of the journal is, it is announced, to be wider 

 than that merely of reporting the proceedings of the 

 institute on the lines usual with professional societies ; 

 its editor indicates that his chief aim will be to make 

 the publication "a medium for the pooling of the 

 experience of those interested in the administration 

 of industrial enterprises, so that it may serve the 

 urgent purpose of assisting in the policy of practical 

 education for members." A prominent feature is to 

 be the special section devoted to the discussion by 

 correspondence of the problems connected with indus- 

 trial administration ; the object of this section is to 

 provide members resident in any part of the world 

 with a medium for exchanging views on administra- 

 tive questions affecting their occupation on an open 

 platform, and in a manner which will, whilst assist- 

 ing members individually, conduce to the greatest 

 usefulness of the institute. Particulars are given of 

 instructional courses, open to members and non- 

 members, to be held in London ; these courses begin 

 on February 2, and deal with production estimating 

 and production costing. The journal contains an 

 abstract of an address on "The Industrial Question" 

 given by Viscount Haldane, O.M., at the inaugural 

 meeting of the institute held on October 23 last. The 

 editorial offices have been established at no Victoria 

 Street, S.W.i. 



An important paper by Lord Lovat on recent pro- 

 gress in British forestry appears in the Journal of 

 the Royal Society of Arts for January 7. It begins 

 with a short account of the movement leading to the 

 passing of the Forestry Act in August, 1919, which 

 created the Forestry Commission and empowered this 

 body to expend 3,500,000!. in afforestation during the 

 ensuing ten years. Lord Lovat further points out the 

 part which private landowners should play in this 

 great national work, and discusses at some length the 

 relations between forestry and such subjects as hill 

 pasture, land given over to sport, small holdings, and 

 NO. 2674, VOL. 106] 



soldier settlements. The paper concludes with an 

 authoritative statement of the operations of the 

 Forestry Commission during its first year. A good 

 beginning has been made ; 69,000 acres of land have 

 been acquired and extensive nurseries started, in 

 which there are growing already 129,000,000 seedlings 

 and transplants. 



The burning coal-seams that are a conspicuous 

 feature in the coalfields of the western United States 

 lead G. Sherburne Rogers (U.S. Geol. Surv., Prof. 

 Paper io8-.\) to remark that a pile of coal exposed 

 to the direct rays of the sun would be liable to 

 become heated and finally to ignite. From his ob- 

 servations in Montana he concludes that " the physical 

 factors promoting spontaneous combustion are a finely 

 divided condition of the coal, a slight increment of 

 heat from an outside source, and a sufficient volume 

 of coal to retard loss of heat by radiation." The 

 absorption of oxygen by coal when warmed generates 

 further heat, and the process is thus self-accelerating. 

 Parr and Francis are quoted as showing that at 

 120° C. to 140° C. a critical stage arises, when the 

 occluded oxygen combines with some of the hydro- 

 carbons, producing carbon dioxide and water, accom- 

 panied by a rapid rise in temperature. Ignition 

 occurs at 350° C. to 450° C. The fine dust of lignite, 

 it appears, may ignite at 150° C, and of gas-coal at 

 200° C. The burning of coal-seams in the west is 

 associated w-ith the cuts formed by small and rapid 

 streams. The metamorphic effects of the heat on 

 the overlying rocks have been studied by the author, 

 and include the production of spherulitic glass and 

 of holocrystalline diopside-plagioclase slag. 



The November and December issues for the past 

 year of the Journal of the Franklin Institute contain 

 an important paper on the annealing of glass by 

 Messrs. L. H. .Adams and E. D. Williamson, of the 

 geophysical laboratory of the Carnegie Institution of 

 Washington. In order to supply the information 

 demanded by the American glass manufacturers as 

 to the proper method of annealing, the authors have 

 determined the rate of disappearance of an initial 

 stress in glass at any temperature. Thev find that 

 the reciprocal of the stress increases with the time 

 at a uniform rate which depends on the kind of glass 

 and the temperature at which it is maintained. A 

 table of rates for common glasses at various tempera- 

 tures is given. .As a result of their investigations the 

 authors recommend that glass, and especially optical 

 glass, should be annealed by raising the temperature 

 in about i^ hours to the value specified in one of the 

 tables as suitable for that glass. This temperature is 

 about 50° C. less than that in common use at the 

 present time. The glass is maintained for four hours 

 at that temperature and then allowed to cool, at first 

 slowly, then rapidly, so that the cooling is over in 

 about three hours, and the whole process lasts onlv 

 eight hours. This is more effective than the old 

 process, involving greater heating and slow cooling, 

 which lasted twenty hours. 



Particulars have reached us of the Elmendorf paper- 

 tester, which indicates the resistance offered by a 



