84 



NA TURE 



[Dec. 3, 1874 



Board these lectures were afterwards published, and 

 they have since formed an important portion of the course 

 of study required for the College examinations. For 

 some time it was universally fell that the book was not in 

 keeping with the advanced state of astronomical science, 

 and that a new and revised edition was necessary. For 

 this purpose, the authorities of Trinity College, who natu- 

 rally have a traditional respect for this treatise, were 

 fortunate in securing so accomplished an editor as Vr. 

 Stubbs, and the co-operation of so distinguished an astro- 

 nomer as Dr. liriinnow. 



Seekers after the romance and history of astronomy 

 will find in this volume few facts recorded in this interesting 

 branch of the science, which the editors have apparently 

 rightly considered as forming no part of a college text- 

 book, for " the student who has made himself so well 

 acquainted with astronomy as to find its history interest- 

 ing will easily procure for himself, from a variety of 

 authors, all the information he can desire." There is 

 also a very limited amount of description of the physical 

 aspects of the larger planets. We rather regret this 

 omission, although there may be reason for doing so, for 

 we believe that the book would have been more generally 

 attractive and useful had some of the results of the 

 numerous modern observations of the physical features 

 of Mars, Jupiter, and Saturn been given. This treatise 

 contains, however, what is far more valuable in a text- 

 book, and which is often slurred over in many popular 

 astronomical works of much higher pretensions, clear 

 and concise explanations, accompanied in many instances 

 with the formuhe of reduction, of various astronomical 

 subjects. Among them we may name the theories of 

 refraction and parallax, the phenomena depending on a 

 change of position on the earth's surface, the motions of 

 the moon and planets in their orbits, eclipses of the sun 

 and moon, the application of astronomy to navigation 

 and geography, the figure of the earth, the masses of the 

 sun and planets, &c. A very fair description of the con- 

 struction and use of the transit instnunent, mural circle, 

 and equatorial is also given, sufficient in fact to enable a 

 non-practised but intelligent observer to understand easily 

 the necessary adjustments required in the use of these 

 instruments. There is an omission, however, though we 

 could scarcely expect to find it inserted, as the method is 

 only adopted in a few of the principal observatories, but 

 a notice of which wc are inclined to think would have 

 been acceptable to many, and w^ould doubtless increase 

 the value of the section on astronomical instruments. 

 We refer to the method of automatic registration of 

 transits on a chronograph, instead of recording them by 

 the ordinary or "eye and ear" method. It is true that 

 the usual manner of making a transit is sufficiently ex- 

 plained, but as the chronographic registration is now fre- 

 quently adopted in the determination of the differences of 

 terrestrial longitudes, as well as in the ordinary registration 

 of transits, we shall always be glad to see a description of 

 the chronograph in every treatise on practical astronomy. 

 Besides considerable alterations in the arrangement of 

 the subjects and additions to the text made by Dr. Stubbs, 

 Dr. Briinnow has contributed new chapters on the phy- 

 sical constitution of the sun and heavenly bodies, on 

 discoveries made by means of the spectroscope, on the 

 proper motions of the fixed stars, and on the general 



advance of stellar astronomy. We need not remark 

 more on these chapters than that the great astronomical 

 reputation of Dr. Briinnow is a sufficient guarantee of 

 their accuracy, and to observe that the principal results 

 of the recent researches are given in a concise form, 

 which makes these chapters most interesting as well as 

 valuable reading. 



We have hitherto given to this excellent treatise an 

 almost unqualified approval, but there arc one or two 

 points of no great moment which wc should like to see 

 corrected in a future edition. Nothing offends the eye 

 of an astronomer more than to sec in an astronomical 

 text-book errors in the orthography of well-known proper 

 names. We have detected a few of such errors which 

 ought to have attracted the attention of the editors if 

 not of the printer. " Flamstead " for FUviislccd might 

 reasonably be passed over in silence ; but when we see 

 " Faumalhaut " printed for Fo})ia!haut, " Fourcault," more 

 than once, for Foucault, " Leomis ' for Lootnis, " Mas- 

 keline," more than once, for Maskelyne, we cannot avoid 

 feehng a pang of regret that in an educational work on 

 the science such inaccuracies should have been allowed 

 to pass. Again, it is unfortun.ate that greater care was 

 not taken to correct the distances and magnitudes of the 

 members of the solar system, depending upon the recent 

 alteration of the value of the solar parallax, especially as 

 the new value of the sun's distance in miles is frequently 

 given. The old value in miles for the velocity of light 

 per second, 192,000, might also have been corrected for 

 the same reason. On page 152, the value of the solar 

 parallax determined from Foucault's experiment is S"'86, 

 not 8"'942, this latter value being sensibly the same as 

 that determined finally by Mr. Stone from a comparison 

 of the Greenwich observations of Mars at the opposition 

 in 1S62, with the corresponding observations made by Sir 

 Thomas Maclear at the Cape and by Mr. Ellery at 

 WiUiamstown, Australia. 



Notwithstanding these few slight drawbacks, we do not 

 hesitate to recommend this most excellent treatise, which 

 is moderate in price, to all who are interested in astro- 

 nomical observations and in the progress of astronomy. 



OUR BOOK SHELF 



A Peep at Mexico. By John Lewis Geiger, F.R.G.S. 

 (London : Triibner and Co., 1S74.) 



Mr. Geiger's book is chiefly devoted to a description of 

 the not well known country westward of the town of 

 Mexico. The route of his journey was from Manzanillo, 

 on the coast of the Pacific, viA Colima, Zacoalco, Guada- 

 lajara, Guanajuato, and Querdtaro, to the capital. 



The book gives but a " peep " at Mexico, but it is 

 a very agreeable one ; for, not entirely relying on his 

 pen to describe what he saw, the author photo- 

 graphed eii route, and forty-five views illustrate his 

 bcok. Although the people, their habitations, and their 

 ways, are the principal topics on which Mr. Geiger 

 writes, yet here and there he gives glimpses of the 

 natural history of the country. For example, the first 

 part of his journey from Manzanillo was along the Laguna 

 de Cuyutlan, which nnis parallel with the shore, separated 

 from the ocean by only a narrow strip of land. " It is 

 almost completely enclosed by mangro\c jungle, which 

 overruns the banks and creates numerous islets by its 

 growth where the water is shallowest. . . . There is no 



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