22 



NATURE 



[Nov. 3, 1887 



matter of convenience to have a common scale of time. It is 

 not essential, but it is highly convenient. In human history we 

 use an astronomic scale of equal parts, designating each unit by 

 a number. In geology no scale of equal parts is available, and 

 we employ the eras and periods, and to some extent the epochs, 

 of the local geologic history first deciphered — that of Europe. 

 These time-divisions bear the same names as the groups, systems, 

 and series of strata whose deposition occurred within them. 



So far as the science of geology is concerned the selection of 

 Europe as its first field of study was a matter of chance, and the 

 adoption of the European time scale as a general standard may 

 therefore be said to have been accidental. Though the local 

 rock scheme on which it is based is natural, the time scale, con- 

 sidered as universal, is arbitrary. Another locality would have 

 afforded a different scale, but its authority would neither be 

 greater nor less. The scale being recognized as arbitrary, and a 

 mere matter of convenience, it is legitimate to modify and fix it 

 by formal convention. The Congress can do good service to 

 geologic technology by putting it in the best possible shape and 

 giving it an official status. In my judgment only a small number 

 of divisions should be admitted, not more than the number of 

 periods of the European scheme. In a general way the dura- 

 tions represented by the co-ordinate divisions should be as nearly 

 equal as practicable, but a certain concession might be made to 

 chronologic perspective on account of our superior opportunities 

 for studying the later history. Some of the shorter periods 

 might perhaps be united under new names. Each line of divi- 

 sion between periods should be defined by means of a strati- 

 graphic plane of division, and this can be done with precision if 

 a locality is made part of the definition. 



Especially should pains be taken to declare the arbitrary 

 nature of the scale. Even with this precaution it will be mis- 

 construed by many, for there is a tendency of the mind to attach 

 undue weight to classification. Wherever we draw lines of 

 separation, we lose to a certain extent the power to recognize 

 continuity. When, for example, the clock strikes twelve on 

 New Year's Eve, time seems to stop and begin again. We speak 

 of the achievements of the nineteenth century — and despite our- 

 selves we think of them too — as though a new industrial epoch 

 began in a.d. 1800. And so it is easy for the beginner in 

 geology to accept as discontinuous the eras and periods of which 

 his text-book treats, and it is hard for him afterward to unlearn 

 the lesson. 



There is reason to believe that confusion of ideas in regard to 

 geologic classification has been fostered by the employment of 

 the same set of names for the divisions of the time scale and for 

 the local terranes on which they are founded. It might be well 

 to furnish the time scale with names suggesting times — such 

 names as the brothers Rogers applied to the terranes of Pennsyl- 

 vania ; but so radical a change is hardly feasible, especially as 

 we should thus lose the mnemonic connection of times with 

 corresponding terranes. I propose, as a means of accomplishing 

 the end with the least inconvenience, that a set of time words 

 be derived from the terrane names by modifying the final sylla- 

 bles. The time words should all have the same termination, and 

 that should differ from any terminations occurring in the terrane 

 names. I suggest for the ending of time words the syllable a/. 

 With such a nomenclature, Jurassic and Devonian would denote 

 only certain European rock systems, while Jural and Devonal 

 would denote periods of the standard time scale ; and we could 

 speak of the Chico-Tejon series as partly Eocenal and partly 

 Cretaceal without seeming to imply the existence in California 

 of the Eocene and Cretaceous systems of Europe. 



A few minutes ago I opposed the differentiation of words by 

 terminations because it abrogated the power of indefinite ex- 

 pression ; I now favour it for the same reason. It is well to be 

 indefinite as to the taxonomic rank of terranes while their 

 characters are imperfectly known, but it is not well to confuse 

 terranes with times. 



It is not to be assumed that a time scale adopted now as the 

 best possible will continue indefinitely to be the best possible ; 

 the day will inevitably come when it can be improved. In the 

 fuller light of the future we may recognize as very unequal 

 periods that we now deem equivalent, and the possibilities of 

 defining pre-Cambrial periods are unlimited. Even now there 

 are announced beneath the lowest fossil-bearing terrane of the 

 Lake Superior region two systems of clastic rocks limited above 

 and below by great unconformities, and Irving demands their 

 recognition as a group, distinct from the Archaean. If his voice 

 heard, the time scale will include an era between the Palseo- 



zoal and the Archaal, and this era will supply the needs of the 

 systematist until great additions have been made to our present 

 knowledge of the older rocks. 



{To be continued.) 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Oxford. — The resignation of Prof. Prestwich and .the 

 continued illness of Prof. Moseley have produced two gaps in 

 the scientific professoriate this term. Though the Professor of 

 Geology has left Oxford, his successor will not be appointed 

 until after Christmas. In Prof. Moseley 's absence the work of 

 the morphological department is being carried on by Mr. 

 Hatchett Jackson and Mr. G. C. Bourne, who has just been 

 elected to a Fellowship at New College. 



In the department of physics. Prof. Clifton is giving no honour 

 lectures, but has an elementary course on mechanics and 

 acoustics. Mr. Selby is lecturing on elasticity and on electro- 

 statics, both treated mathematically. At Christ Church, Mr. 

 Baynes gives lectures and practical instruction in electricity and 

 magnetism. Sir John Conroy and Rev. F. J. Smith are 

 lecturing on elementary physics at Balliol and Trinity, 



The chemical department at the Museum has been strengthened 

 by the addition of Mr. V. H. Veley to the staff ; the usual 

 courses of lectures are being given by Mr. Fisher and Dr. 

 Watts, and Prof. Odling is lecturing on glycerine and its deriva- 

 tives. At Christ Church, Mr. Vernon Harcourt has a class for 

 quantitative analysis, and lectures on elementary chemistry. 

 Sir John Conroy is lecturing on chemical physics at Balliol. 



The Physiological Laboratory is continuing its usual work with 

 little alteration. Prof. Burdon Sanderson's lectures are on 

 circulation, respiration, and bodily motion. 



Prof. Balfour, besides lecturing on extinct plants for the 

 Professor of Geology, is giving a course on general morphology. 

 Dr. Tylor continues to expound the Pitt-Rivers Collection, a 

 fresh portion which will shortly be rearranged and opened to 

 the public. 



Mr. Primrose McConnell is lecturing on the principles of 

 agriculture, mainly for the benefit of India Civil Service 

 candidates. 



During this term there will be an examination for Scholarships 

 in Natural Science at Balliol, Exeter, Christ Church, and Trinity 

 jointly, beginning on November 17. 



A pamphlet has just been issued from the Clarendon Press 

 giving full information as to the methods of obtaining medical 

 degrees in Oxford, and the instruction in medicine provided by 

 the University. 



Cambridge. — The Museum and Lecture Rooms Syndicate 

 have issued another report pressing for new accommodation for 

 Pathology and Physiology, and suggesting that the department 

 of Pathology, including its Museum, could be located in the old 

 chemistry buildings when the new laboratory is completed. 

 They recommend the building of new rooms for Human 

 Anatomy and Physiology on the Corn Exchange site at the 

 northern end of the Museum site. It is an important feature of 

 this scheme that it would leave free the present Human 

 Anatomy Schools and Museum to be added to the frontage 

 available in Downing Street for a Geological Museum. 



Messrs. W. H. Macaulay and W. B. Allcock have been 

 appointed Moderators for the year beginning May i, 1888. 

 Messrs. J. Larmor and W. Welsh are appointed Examiners in 

 Part I. of the Mathematical Tripos for the same year. 



Dr. Smith's prizes for the present year have been adjudged 

 as follows : — (i) Mr. Augustus Edward Hough Love, St. John's 

 College, for an essay on " Small Free Vibrations and Deforma- 

 tion of a thin Elastic Shell," and on " The Force and Forced 

 Vibrations of an Elastic Spherical Shell . containing a Given 

 Mass of Liquid." (2) Mr.^ Arthur Berry, King's College, for 

 an essay on " Joint Reciprocants." 



SCIENTIFIC SERIALS. 



The Quarterly Journal of Microscopical Science for August 

 1887, vol. xxviii. part I, contains the following papers : — On the 

 anatomy of the Madreporia, part 3, by Dr. G. Herbert Fowler, 

 (plates i. and ii.) In this memoir the author deals with the 



