i\UGUST I, 19 1 8] 



NATURE 



433 



bear the stamp of truth, but it appears certain that 

 no bodies prepared by the method Herodotus describes 

 have been found so far. 



According to the Scientific Ainericati for June 22, 

 • the American Government has received thousands of 

 suggestions for the protection of sea-going vessels from 

 attack by submarine. Often the same suggestion is 

 made by many different inventors, the great majority 

 of whom show a lamentable ignorance of the condi- 

 tions which prevail at sea. Seven devices are illus- 

 trated, four of which consist of padding for the hull, 

 which would either increase the resistance of the 

 ship and diminish its speed greatly, or would be 

 carried away by the first heavy sea. Another device 

 deflects the torpedo below the keel, the inventor not 

 appearing to know that it would be fired by the 

 deflection. The other devices are for preventing the 

 sinking of the vessel after she has been struck, and 

 involve either an inner hull or a series of air-bags 

 which can be pumped up and pulled under the side 

 of the vessel struck. Would-be inventors of devices 

 for this purpose might save themselves and the 

 Government Departments much trouble bv consulting 

 this article. 



Attention may be directed to a very useful article 

 by Dr. P. E. Spielmann in the Chemical Trade 

 Journal for July 6 and the three previous issues, giving 

 a summary description of the constituents of coal-tar 

 and their properties. A large number of substances 

 has been found in coal-tar — from three hundred to 

 four hundred, of which about one hundred and fifty 

 have been determined quantitatively and ninety de- 

 finitely isolated. On a large scale only four are 

 separated as the pure individual substances, namely, 

 benzene, toluene, naphthalene, and phenol, though 

 others, such as xylenes, cresols, and the hydrocarbons 

 of solvent naphtha, are used in considerable quantities 

 in the form of mixtures of their homologues. The 

 article, which is based upon a German account with 

 additions and modifications, is designed to give a 

 general survey of the lesser-known as well as the 

 more valuable substances obtainable. By reason of 

 the exploitation of the coal-tar industrv in Germany 

 the minute examination of the constituents of tar has 

 so far been due largely to German chemists. The 

 results obtained are of great value, and it is hoped 

 that detailed and difficult work of this kind will in 

 the immediate future be carried on in this countrv, 

 since our chemists are fully capable of doing it. In 

 anv case, the information collected will prove service- 

 able. 



The first of a series of articles on time studies for 

 rate setting on machine tools appears in Industrial 

 Management (The Engineering Magazine) for June. 

 The author, Mr. Dwight V. Merrick, has had excep- 

 tional opportunities of studying this important sub- 

 ject. Some nineteen years ago he became associated 

 with Dr. Taylor, and for the last fifteen years has 

 specialised on the taking of time studies and the 

 setting of tasks and rates. He also possesses ihe 

 faculty of setting down in clear, concise style the 

 knowledge he has gained during lengthy investiga- 

 tions, and his articles can be recommended confidently 

 to any who wish to become further acquainted or to 

 make person il experiments with Dr. Taylor's efficiency 

 methods. Full instructions are given for the practical 

 carrying out of time studies arid for the analysis of 

 the results. The matters dealt with include : — 

 (a) Study of the work and conditions that influence 

 its performance; (b) analysis of the work into its 

 elements; (c) obsei-ving and recording the elapsed 

 time for the performance of each of the elements ; 

 NO. 2544, VOL. IOl"| 



(d) study and analysis of the records obtained in (c) ; 



(e) determining a just time for the performance of 

 each of the elements ; (/) preparing from the time- 

 study records an instruction card, including the 

 determining of an allowance for fatigue and unavoid- 

 able delays. The first article includes formula? and a 

 set of interesting graphs giving the "variation allow- 

 ance," i.e. the additions that must be made to the 

 actual sum of the unit times in order to take care 

 of the factors that slow down work. Fatigue i^ one 

 of the major factors, and its influence is relativelv 

 diminished as the percentage of handling time is les- 

 sened for the complete cvcle of operations. Those 

 interested will find a great deal of valuable practical 

 information in these articles. 



Sir William Ramsay before his death had compiled a 

 biography of Dr. Joseph Black, whose fundamental ex- 

 periments on chemical combination and on heat made a 

 lasting impression on science. This volume, with an 

 introduction by Prof. F. G. Donnan on Sir William 

 Ramsay himself, illustrated by sundry reproductions 

 and portraits, is now in the press, and will be pub- 

 lished by Messrs. Constable. Besides an account of 

 Dr. Black's life and work, there are ?:ome of his letters 

 and descriptions of academic 'ife in Glasgow and Edin- 

 burgh of the eighteenth century. 



Messrs. J. Wheldon and Co., ^8 Great Queen 

 Street, W.C.2, have shown enterprise in issumg a 

 catalogue, called by them a "War Economv '" cata- 

 logue, of books relating to botany likely to be of 

 especial interest and service at the present time. It 

 contains some 2000 items, arranged convenientlv under 

 the headings of .Agriculture, Husbandrv, and Garden- 

 ing (general subjects). Cereals and Bread, the Flowor 

 Garden. Forestry, Timber, etc.. Fruit and Fruit Trees, 

 Grape Vine, etc.. Grasses and Forage Plants, Herbals, 

 Hybridity. Heredity, etc.. Orchids, Vegetable Gar- 

 dening, Economic "Botany, and MedicaF Botany. It 

 will doubtless appeal to many readers of Nature. 

 Copies are obtainable from Messrs. Wheldon for the 

 sum of twopenc". 



OUR ASTRONOMICAL COLUMN. 



The New Star in Aouila. — The decline of the new. 

 star appears to be proceeding very slowly, the bright- 

 ness on July 27 being still about equal to that of the 

 neighbouring 4th magnitude star Serpentis. The 

 visual spectrum, as observed by Prof. Fowler, has 

 shown but little change during the past fortnight. The 

 bright lines of hydrogen and the band A 464 were 

 very conspicuous throughout this per'od when observa- 

 tions were possible, and the green line about A 501, 

 which is possibly identical with the chief nebular Tine, 

 was of nearly the same brightness as H^. Three 

 fainter lines in the vellow, about AA 588, 576, and 568. 

 also remained visible. 



The General Magnetic Field of the Sun. — ^The 

 results of a further investigation of the Zeeman effects 

 due to the general magnetic field of the sun have been 

 given by Messrs. Hale, Seares, Van Maanen, and 

 Ellerman (.Astrophys. Journ., vol. xlvii., pp. 206-54). 

 The photographs were taken in the third order of the 

 75-ft. grating spectrograph in connection with the 

 ii;o-ft. tower telescope at Mount Wil-son. With the 

 aid of suitable polarising apparatus the observations 

 are reduced to the measurement of line displacements, 

 but these are so minute, and the lines so wide in com- 

 parison with their shifts, that definite evidence of the 

 reality of the displacements has been established onlv 

 after very great labour. It is satisfactory to find, 

 I however, that the twenty-six additional lines which 



