Dec. 17, 1874 



NATURE 



133 



at Trinity College, but these are restricted to members of 

 those colleges which are associated with Trinity for Natural 

 Science studies. 



The great hindrance to the success of the Cavendish 

 Laboratory at present is the system fostered by the 

 Mathematical Tripos. The men who would most naturally 

 be the practical workers in the laboratory are compelled 

 to refrain from practical work if they would gain the best 

 possible place in the Tripos list. Very few have courage 

 so far to peril their place or to resign their hopes as to 

 spend any valuable portion of their time on practical 

 work ; for, while they might be acquiring sound physical 

 conceptions and going through long laborious details, 

 • others are assiduously cramming book-work, wearing out 

 their energy in attacking those problems which are here 

 set before the student as affording the best mental 

 training, and in learning those short cuts and dodges which 

 conduce to obtaining marks in an examination. For a 

 man to do practical work in physics at Cambridge impKes 

 considerable exercise of courage and self-sacrifice. 



Students of the foregoing subjects, however, have better 

 facilities for study than students of Biology. In Practical 

 Physiology and fiistology almost everything is required. 

 A large room, properly lighted and fitted, is needed for 

 elementary courses ; and, considering the numbers already 

 attracted to Dr. Foster's summer and winter classes, in 

 spite of difficulties and defects, it would seem desirable 

 to provide accommodation for at least a hundred students. 

 Rooms should also be provided, specially adapted for 

 advanced work in Histology, for researches in Physi- 

 ology, for preparation of experiments and of materials for 

 the classes, and, in addition, a good lecture-room. 



In Comparative Anatomy and Zoology the museum has 

 been much improved in the last few years, but its growth 

 is greatly restricted by want of funds. The accommo- 

 dation for practical dissection of animals consists only of 

 the superintendent's private room, which, at the cost of 

 great inconvenience, has been generously thrown open to 

 students. 



Finally, as regards P>otany, while there are a good 

 garden and a carefully kept herbarium for systematic 

 study, there is no class of any kind for practical study of 

 Vegetable Histology and Physiology. And yet, recently, 

 the standard for obtaining an ordmary degree in Botany 

 has been considerably raised, and students are expected 

 to show knowledge of the forms, sizes, and development 

 of cells of every kind. The demand for an acquaintance 

 with Vegetable Histology, which, to be real, must be ac- 

 quired by assiduous and carefully directed microscopical 

 study, while no instruction in such work is given, puts a 

 premium on cramming of the most unfruitful kind, and 

 reduces natural science studies to a lower level than those 

 mathematical and classical studies whose exclusive pur- 

 suit scientific men desire to see abandoned. It would be 

 better to examine only in those portions of morphology 

 and classification which can be learnt in a botanic 

 garden, than to set elaborate questions in Histology and 

 Physiology which necessitate elaborate cramming on the 

 part of the student. G. T. Bettany 



Cambridge, Dec. 10 



M. BECQUEREL ON SOLAR PHYSICS 



THE Paris Academy of Sciences having appointed a 

 Commission to consider the founding of an Observa- 

 tory for Physical Astronomy in the vicinity of Paris, M. 

 Becquerel the elder, a member of the Commission, has 

 expressed his opinion on the subject in a report of which 

 the following is a translation : — 



To study the physical constitution of the sun and star=. 

 Astronomy employs in general telescopes and the spec- 

 troscope ; this last instrument shows us that the heavenly 

 bodies are composed of the same elements that are found 

 in the earth ; whence it may be concluded that the forces 



governing matter are of universal existence. This question 

 I have considered in a work now going through the press 

 and which will appear before the end of the year ; its 

 title is " On the Physico-chemical Forces and their Inter- 

 \ention in the Production of the Phenomena of Organic 

 and Inorganic Nature." All questions relating to these 

 subjects are there treated, not theoretically, but by the 

 experimental method. 



I have endeavoured to show that to arrive at a know- 

 ledge of the sun's constitution it is necessary to call to 

 our aid the geological constitution of the globe and 

 volcanic phenomena from the earliest times down to the 

 present epoch. 



The following are the reasons which have led me thus 

 to deal with the subject : — 



The identity of formation of the sun and earth and of 

 all the planets which gravitate around our principal star 

 being admitted, the conclusion may be drawn that his 

 present physical condition is the same as that of our 

 planet during the first periods of its formation, when the 

 crust did not exist or had but little thickness. The cooling 

 of the earth has been considerably more rapid than that 

 of the sun by the effects of celestial radiation, the volume 

 of the sun being 1,326,480 times that of the earth. It is 

 thus permitted to compare the chemical and physical 

 elfecis occurring in the sun at present with those which 

 were produced in the earth at its origin, from which con- 

 clusions may be drawn as to the actual constitution of 

 this star. 



The collection of vapours which constituted the earth, 

 submitted to a gradual cooling, passed successively from 

 the gaseous to the liquid state, after which its surface 

 became covered by a solid crust, of which the thickness 

 increased with time. There were then produced a mass of 

 chemical and physical phenomena. 



We may distinguish three principal calorific epochs 

 during the formation of our planet. 



The first is that in which all the elements were in a 

 gaseous state in consequence of a temperature excessively 

 elevated ; all the constituents were then dissociated. 



The second is that in which, the temperature being 

 sufficiently lowered, affinities commenced to exercise their 

 action ; the compounds formed passed successively from 

 the gaseous to the liquid and solid states. During all the 

 chemical reactions which occurred there would be pro- 

 duced an enormous disengagement of electricity arising 

 from the energy of these reactions, and, as a consequence, 

 a recomposition of the two electricities which would rend 

 with vivid gleams the atmosphere already formed. 

 Thunder would burst fotth from all parts. 



The third epoch is that in which the temperature, being 

 sufficiently lowered and below 100^, the quantity of water 

 formed would increase so much the more as the tempera- 

 ture was less elevated. This primordial water contained, 

 probably, carbonic, sulphuric, and other acids which 

 would saturate bases ; it is to the reactions produced 

 that must be attributed the formation of the great masses 

 of limestone found in various parts of the earth's crust. 



I have been led also in my work to treat of the calorific 

 state of the earth in the first phases of its formation, as 

 also of the volcanic phenomena of the same epochs. 



As a consequence of the subjects discussed, I have 

 been led to show that atmospheric electricity had a solar 

 origin, and is the cause of the aurora and probably of the 

 luminous phenomena which are produced beyond our 

 atmosphere. I here limit myself to the indication of the 

 consequences to which the study of the forces of nature 

 has led me. 



From what precedes it will be seen that the study of 

 the constitution of the sun requires the conjunction, not 

 only of astronomy, but of observers having general know- 

 ledge in Physics, Geology, and Chemistry, and possessing 

 a thoroughly practical k lowledge of the spectroscop?. 



K. M. 



