Oct. 25, 1883] 



NATURE 



619 



" Among the drawbacks that may be specially named is j 

 the ignorance of legislators, of executives, and electors on 

 this subject." 



With this English readers will entirely concur. The 

 next subject proposed as a definite object of study is that 

 of economic entomology. Such enemies as the Colorado 

 beetle, the wheat midge, the turnip fly, the wire worm, or 

 the locust are among the most formidable which the 

 farmer has to contend with. The depredations of the 

 wheat midge alone may be appraised at over 3,000,000 

 bushels annually in Great Britain. Our Royal Agri- 

 cultural Society has taken up this matter, and Miss 

 Ormerod's book upon injurious insects is full of informa- 

 tion and suggestions concerning it. This certainly is a 

 branch of knowledge which requires labourers. From it 

 we are led to reflect upon the important bearing of the 

 study of entozoa upon agriculture, and especially upon the 

 pathology of farm stock. The improvement of the 

 American pastures appears to be desirable. According 

 to Prof. Beal, a dozen sorts of grasses probably cover 

 nineteen-twentieths of all the cultivated meadow-land from 

 Maine to Texas. As the grass family is large, containing 

 from 3100 to 4000 or more species, it is naturally thought 

 that a few more might be found suitable for various parts 

 of this immense area. 



Not only is much to be done in the introduction of new 

 grasses but in selecting and propagating varieties of the 

 same grass. " Plants of red clover vary amazingly in 

 man> respects." " I believe our fields of red clover to- 

 day contain nearly or quite as great a variety of plants 

 as would a field of Indian corn, if we were to mix in a 

 little seed of all the varieties cultivated in any one State." 

 This is startling, but quite in accord with the wonderful 

 variations observable in plants of Italian and perennial 

 rye grass and other grasses and clovers. Thus Prof. 

 Beal indicates various paths for improvement, and urges 

 the vast importance of agricultural experiment stations, 

 where work bearing upon the various subjects enumerated 

 may be carried on by competent persons. There is no- 

 thing very new in all this. The importance of agricultural 

 research has been often declared in our own country from 

 the days of Sir Humphry Davy until now : but too often 

 the voice has been as of one crying in the wilderness. 

 Some good has been done, and we may expect a more 

 rapid development of these ideas ere long. Scientific 

 agriculture was never more popular than at present, and 

 the number of agricultural students attending syste- 

 matic courses of instruction is greater now than at any 

 previous time. Agriculture has become a recognised 

 subject of the Science and Art Department, and we 

 note a disposition on the part of scientific men to 

 attach greater importance to the study of domesticated 

 animals and cultivated plants than formerly. We owe 

 much of this to Darwin. He, more than any other man, 

 raised the scientific interest of these humbler subjects of 

 zoological and botanical science, which had previously- 

 been passed by scientific men with scarce concealed con- 

 tempt. Anthropology has also done much to throw a 

 halo of interest around those animals and plants which 

 have been associated for long ages with man. Hence 

 there is a greater bond of union between the present 

 generation of scientific men and the agriculturist than 

 existed a generation since, and it is probable that this 

 sympathy will increase and fructify for the benefit of all. 



Johx Wrightson 

 College of Agriculture, Downton, Salisbury 



THE GREAT NEBULA IN ORION 



IT is a fortunate circumstance for students of nebular 

 astronomy that within a short time that branch of 

 science has been enriched by a monograph and a photo- 

 graph, each perfect in its way, of one of the grandest 

 objects in the heavens. The monograph is from the pen 



of Prof. Holden, 1 whose name is a guarantee of thorough- 

 ness ; the photograph we owe to Mr. Common, who at 

 one bound has distanced all predecessors, and has shown 

 us that in the future we may hope for permanent records 

 of the nebuke as perfect as those of the surfaces of the 

 sun and moon produced by Janssen and Rutherfurd. 



In the present article we propose to refer toboth these pro- 

 ductions with a view of showing how terribly physical astro- 

 nomers are losing time in not throwing all their energies into 

 the production of photographic records whenever possible. 

 In Prof. Holden's paper we are enabled to see how, two 

 hundred years ago, time was lost and false issues raised 

 because the astronomers of those days had never learned 

 to draw ; indeed it is terrible to look at the collection of 

 rude, crude, and almost impossible sketches by Huyghens, 

 Mairan, Picard, Long, Le Gentil, and others which he 

 has brought together. Mr. Common on his part has 

 shown us that it is possible to photograph, with about half 

 an hour's exposure, all the details shown in the most 

 careful drawings made by men with artistic training as 

 the result of months — and we may almost say years — of 

 labour ; such drawings as we owe to Bond, Herschel, and 

 Lord Rosse. Mr. Common's photograph, it should also 

 be said, includes the whole nebula, while the monograph 

 is confined to the central portions. 



The most convincing argument, however, in favour of 

 the more serious employment of photography in our obser- 

 vatories, that we can use is to show the relation of the 

 photograph to the memoir. The latter commences as 

 follows: — " The main object of this memoir is to leave 

 such measures and descriptions of the brightest parts of 

 the nebula of Orion as shall enable another person ob- 

 serving in after years with the same telescope, under like 

 conditions, to say with certainty whether or no changes 

 have occurred in those parts of this nebula." 



To carry out this object everything touching the nebula 

 written between 1618, when Cysat of Lucerne discovered 

 it, and Holden's own observations of 1SS1 has been 

 brought together and coordinated, and the labour and 

 time this has required may be gathered from the fact that 

 the list of the more important papers relating to the 

 nebula consulted in writing the memoir cover four pages 

 quarto and includes about two hundred entries. 



Now it is not too much to say that in the case of an 

 astronomer taking up the question a century hence, as 

 Prof. Holden has now done, he would prefer the single 

 photograph taken by Mr. Common in thirty- seven 

 minutes to all the literature so admirably brought to- 

 gether by Prof. Holden ; and if the world must in the 

 meantime lose either the memoir and the records of the 

 human effort of l\ centuries on which it is based, or the 

 photograph, then it is to be hoped that the photograph 

 will be spared. We say this the more readily because 

 we are certain that Prof. Holden will agree with us. 



But it is time that we should refer to the memoir sepa- 

 rately. It is preceded by Bond's magnificent drawing, 

 1859-63, and an index chart giving the minute system of 

 nomenclature necessarily adopted to distinguish the 

 various bright masses, dark channels, spirals, &c, of the 

 portion under notice. The nomenclature is that of Sir 

 John Herschel, Lord Rosse, and Liaponoff in the case of 

 the nebula proper, while the stars are laid down from 

 Bond's catalogue. The index map is indeed the only 

 part of the memoir with which we have any fault to find, 

 for it attempts too much, and for that reason will be of 

 restricted use to those whose optical power is not of the 

 greatest. 



The drawings and memoirs are considered in chrono- 

 logical order ; the woodcuts bring up the drawings to the 

 same scale, or nearly so. We have the woodcut first, 

 and then extracts of the ipsissima verba of the observa- 

 tions. Everything touching the central portion is given 



■ "Washington Astronomical and Meteorological Observations," vol. 

 xxv.. 1878. Published 1882. 



