November 29, 19 17] 



NATURE 



247 



is the impossibility of eliminating some forms of 

 " systematic " error, which are too likely to be 

 variable to be strictly systematic, such as the dif- 

 ference between the indications of a thermometer, 

 under various conditions of exposure, and the real 

 temperature of the air. Another is an error 

 neither accidental nor systematic, but due to the 

 fact that the data are meteorological; a good 

 example of this is afforded by the mean diurnal 

 variation of air temperature as shown on (a) over- 

 cast or (b) cloudless days. 



Dr. Ryd regards harmonic analysis applied to 

 such data as an excellent interpreter, but a very 

 untrustworthy probe. The known periods — the day 

 and the year — are unexceptionable, and the varia- 

 tion from hour to hour in one case, and from day 

 to day, or preferably from "pentad " to "pentad," 

 in the other, are obviously lit subjects for analysis. 

 Dr. Ryd prefers to use both sine and cosine 

 terms instead of the usual transformation, because 

 the determination of mean error is more direct 

 when two constants enter similarly. This is clearly 

 important, as the mean error is a vital considera- 

 tion. Analysis for testing a real period, such as 

 one of the lunar periods, on the meteorological 

 data is not quite so risky as tentative fishing for 

 an unknown period, in which case at least one 

 coefficient, according to Dr. Ryd, must be five 

 times its probable error before it can be regarded 

 as likely to be real. 



The brochure is divided into two sections, the 

 first dealing generally with such routine problems 

 as the computation of the mean error, smoothing 

 and adjustment of observational data, and har- 

 monic analysis, with an additional chapter on 

 secondary minima and maxima in the annual varia- 

 tion of the temperature, in which the author deals 

 with the proverbial "Ice-men" of May ii, 12, and 

 13, and exposes the weakness of Dove's supposed 

 proof of the reality of this legendary phenomenon. 

 The second part deals fully with " mechanical " 

 adjustment, factors of variation, and sugges- 

 tions on the choice of adjusting formulae, of which 

 several are given, and a longer chapter is devoted 

 to the working out of four concrete examples, 

 viz. the" hourly inequality of air temperature, 

 Greenwich, 1849 to 1868; and of pressure, Green- 

 wich, 1854 to 1873; the annual inequality of pres- 

 sure, Batavia, 1876 to 1905; and the annual varia- 

 tion of temperature, Copenhagen, 1875 to 1910, 

 the last being a case of partial data — only three 

 observations at fixed hours of the day,, instead of 

 the full set. 



Dr. Ryd reminds the reader that when data 

 such as July air temperature for twenty years are 

 entered in rows for days and in columns for years, 

 they cannot be analysed similarly in both direc- 

 tions, inasmuch as the successive days are not 

 independent, while the columns are. He also dis- 

 cusses at some length the " order " to which 

 harmonic analysis, if used for adjustment, should 

 be pushed, with hints for saving labour ; but on 

 the whole he prefers the " mechanical " adjust- 

 ment with a suitable formula in the majority of 

 cases, aqd thinks this method less liable to intro- 

 duce new errors into a problem. W. W. B. 

 NO. 2509, VOL. 100] 



NOTES. 



Sir Akchiiuld Geikie, O.M., who has long been a 

 correspondant of the Paris Academy of Sciences, has 

 now been elected an associate member of the academy. 



The Times announces that the report of the Depart- 

 mental Committee on salaries of teachers will be issued 

 within the next few weeks. The report of Sir J. J. 

 Thomson's committee on science teaching is also ex- 

 pected at an early d^te. 



The council of the Royal Meteorological Society has 

 awarded Dr. H. R. Mill the Symons gold medal for 

 1918 "for distinguished work in connection with 

 meteorological science." The medal will be presented 

 to Dr. Mill at the annual meeting of the society in 

 January next. 



At the meeting of the Chemical Society to be held 

 on December 6, Dr. F. L. Pyman will deliver a 

 lecture entided "The Relation between Chemical Con- 

 stitution and Physiological Action." 



The Hon. Sir Charles Parsons, member of council 

 of the Institute of Metals, is to give the eighth annual 

 May lecture before the institute next spring. He will 

 deal with the subject of the formation of diamonds, 

 with the artificial production of which he has been 

 experimenting for more than thirty years. 



The death of Mr. Alexander Adamson is announced 

 in Engineering for November 23. Mr. Adamson was 

 born in Glasgow in 1846, and took a prominent part in 

 the evolution of the modern Atlantic liner, and was 

 later identified with the early stages of development of 

 the Barrow works, now the most important naval 

 armament and munition works in the kingdom. He 

 served for some years on the council of the Institution 

 of Naval Architects. 



The death is announced in the Chemist and Druggist 

 of November 24 of Prof. Charles Caspari, jun., dean of 

 the Department of Pharmacy in the University of 

 Maryland, and Food and Drug Commissioner of the 

 State of Maryland. Prof. Caspari 's "Treatise on 

 Pharmacy " is well known on this side of the Atlantic. 

 In addition, Prof. Caspari was one of the editors of 

 the U.S. Dispensatory and a member of the Revision 

 Committee of the United States Pharmacopoeia. 



We regret to note that Engineering for November 

 23 announces the death, from heart failure, of Mr. 

 Peter Denny, a member of the Dumbarton family 

 which has done so much work to establish shipping and 

 marine engineering on a truly scientific basis. In this 

 work Mr. Denny took an effective part, and also fulfilled 

 in a marked degree those varied duties of an employer 

 of labour connected particularly with the social life of 

 the worker. Mr. Denny, who was in his sixty-fifth 

 year, joined the Institution of Naval Architects in 1880. 



At the monthly meeting of the Zoological Society of 

 London, held on November 21, it was stated that 

 during the months of August, September, and Octo- 

 ber 281 additions had been made to the society's 

 menagerie. Of these, perhaps the most interesting are 

 a brindled gnu, from South Africa, and an anoa, from 

 Celebes. Having regard to the times, one can scarcely 

 be surprised at the announcement of a falHng-off in 

 receipts during 1917. From January i to October 31 

 this amounts to 3806L Happily, the number of fellows 

 elected and re-admitted shows an increase of thirteen, 

 as compared with the corresponding period last year. 



In his presidential address to the Royal Statistical 

 Society on November 20 Sir Bernard Mallet referred 

 to the damage which the present war must inflict upon 

 this and other nations. The United Kingdom has lost 



