September 26, 1907J 



NA TURE 



547 



and accept his ruling. All will be cautious how they 

 dissent from his expressed opinions. But it seems 

 to us tliat to recommend the wholesale rejection of 

 a large number of published measures of double stars 

 is a drastic proposal, from which a less stern critic 

 than the author might well recoil. It may be 

 admitted that the possessors of small telescopes have 

 always struggled to measure objects for which their 

 instruments were unfitted. Indeed, a double-star 

 observer never seems happy unless he is trying to 

 measure something he can see very imperfectly. 

 But simple dissatisfaction with the manner in which 

 an observation has been made does not olfer any 

 adequate criterion for the rejection of doubtful obser- 

 vations, and we can hardly accept the assertion " that 

 there need be no difficulty or hesitation in deciding 

 as to the proper material to be used." This, as it 

 stands, is a hard saying, and we may very well 

 doubt if we have correctly understood the author. 



He is on safer ground when he declines to deduce 

 any inferences which might be based on tlie grouping 

 of statistics. He is at present content to collect facts 

 and to regard as premature any attempt to establish, 

 or even suggest, theories on the limited information 

 at command. The remark is made that very little 

 has been done in the way of finding close pairs below 

 the ninth magnitude, and that the effect of recent 

 discovery in this direction may controvert the conclu- 

 sions drawn from the older measures. This may 

 doubtless be true, but the lack of sufficient data has 

 seldom prevented the adoption of a working hvpo- 

 thesis. Certainly when Prof. Burnham sums up 

 what has been accomplished in a century of double- 

 star observing the results seem somewhat meagre 

 for theory building, and emphasise the necessitv for 

 that careful and systematic measurement upon which 

 he insists. There are only eighty-eight systems for 

 which orbits have been found, and of this number 

 only thirty-four can be regarded as of any value. 

 .'Vs to the remaining fifty-four systems, the periods 

 and " all the elements of the orbits are wholly uncer- 

 tain and worthless. They cannot be regarded even 

 as approximations . . . and in some instances it is 

 not certain that they are physical systems at all." 

 This severe criticism can be justified. Perhaps some 

 of these indecisive results and the eagerness to build 

 upon unsuitable observations may be traced to the 

 influence of Herschel, and the apparent success that 

 attended his ingenious device for deriving an 

 approximate orbit. iVIore rigorous methods have, 

 however, given results of scarcely greater trustworthi- 

 ness, and the tendency now is to leave double-star 

 orbits severely alone. 



It may be of greater practical utilitv to note that 

 our knowledge of double stars has suffered from the 

 want of organisation among observers. As the 

 author puts it, " .Since the observations of Struve the 

 work of micrometrical measurement of double stars 

 has not been wiselv distributed. .A vast amount of 

 time has been practically wasted in the duplication of 

 measures of the prominent and familiar pairs and 

 in observing objects which need no attention exceot 

 at long intervals." But Prof. Burnham may here be 

 reminded that it is not enough to suggest that the 

 working lists of double stars should be more carefully 

 selected. What is wanted is authoritative leadership 

 and symoathetic guidance. Such an influential 

 position the writer of these books might worthily 

 occupy. His competency no one would question. 

 The necessitv for cooperation among astronomers 

 and the judiciou'; husbandintf of resources is be- 

 coming more and more recognised. The beneficial 

 effect of oreranisation in cooing with large masses of 

 work is acknowledtred. Isolated and unmethodical 

 labour is accompanied by many evils, but none more ; 



NO. 1978, VOL. 76] 



noticeable than that of overlapping and needless 

 duplication. These evils cannot be entirely avoided, 

 but they can be reduced to a minimum. 



Overlapping may to some extent be beneficial. An 

 example is supplied by the very admirable work 

 which Mr. Lewis has lately published through the 

 Royal Astronomical Society. But it is not often that 

 two experts work on so nearly parallel lines. Mr. 

 Lewis has done in a very thorough and masterlv 

 manner for the Struve stars what Prof. Burnham has 

 accomplished for a larger number. Mr. Lewis's work 

 may be the more efficient, in the sense that it enables 

 us to dispense with a larger number of original 

 authorities, but there would have been no great dif- 

 ficulty and some advantage in combining the merits 

 of botli compilations. It is not necessary to give 

 illustrations of the way in which observations are 

 duplicated. It is difficult to quote instances in which 

 independent lines of investigation are being pursued. 

 The Lick Observatory has made the search for close 

 double stars of feeble magnitude peculiarly its own. 

 In this department is doubtless found an admirable 

 employment for large optical power. Mr. Burnham 

 has added many new doubles to our catalogue, but 

 apparently finds a sufficient field for his energy in the 

 re-measurement of recognised doubles. Throughout 

 the Lhiited States a vast number of observers are 

 interested in double stars, but in their work it is 

 impossible to recognise any well-developed plan. On 

 this side of the Atlantic, besides the excellent work 

 that is being done at the Royal Observatory, which 

 again demands large aperture, we have an army of 

 amateurs, headed, we may sav, by Mr. Maw, the 

 late president of the Royal Astronomical Society, 

 whose contributions to the general store would be 

 increased in value if designed to form part of a 

 definite scheme. Too often double-star measure- 

 ment is the refuge of the leisured amateur, who finds 

 in this kind of work an agreeable occupation. Such 

 irresponsible observers stand particularly in need of 

 direction, and if some scheme of cooperation could be 

 formulated. Prof. Burnham's intimate acquaintance 

 with the subject would be of immense assistance. 

 He has admirably arranged the material that is to 

 be observed ; he has made us apprehend the extent 

 of the field of labour and the abundance of the 

 harvest ; he has shown what can be done by unweary- 

 ing industry and painstaking perseverance; let him 

 complete his work by organising the labourers and 

 infusing into their work system and continuity. 



FOOD INSPECTION AND ADULTERATION. 



CIR JAMES CRICHTON BROWNE, 'as president 

 --^ of the Association of Sanitary Inspectors, de- 

 livered last week the customary address at the annual 

 meeting of the association. His remarks, devoted 

 largely to the question of purity in foodstuffs, were a 

 forcible presentation of matters which, well known to 

 those concerned in the problem of food-control, de- 

 serve the serious attention of a wider circle, since as 

 consumers and as citizens all are interested in the 

 points brought forward. 



The most important topic dealt with was that of a 

 pure milk supply. It is " the primary and paramount 

 food question." There is no need to enter here into 

 details of adulteration, but it may be slated that 

 according to the Local Government Board reports ten 

 per cent, of our mill< is eitlicr adulterated with water 

 or impoverished by the abstraction of fat, or both ; 

 whilst a much larger proportion is so manipulated as 

 to leave it only just within the official limits taken as 

 criteria of genuineness. Moreover, the practice of 

 sophistication appears to be extending. 



