514 



NATURE 



\Oct. 24, 1872 



OUR BOOK SHELF 



F.lnncHtarv Ccoloo'- ^ Course of Nine Lectures, spe- 

 cially adapted for the use of Schools and Junior Stu- 

 dents. By J. C. Ward. (London : Triibncr & Co.) 

 This little volume is a praiseworthy attempt to popu- 

 larise the study of Geology. The descriptions and 

 explanations are, for the most part, well done, and will 

 be easily followed by those for whom the book has been 

 written. The introductory "lectures," which treat of the 

 oritjin and classification of rocks, of geological agents, of 

 waste and renovation, and of physical geography, are the 

 most satisfactory. When the author comes to deal with 

 tlie geological history of the English formations, the 

 necessity for condensation often leads him into obscurity ; 

 but upon the whole he has managed to give a more read- 

 able account than will be found in other introductory 

 lesson books. As the lectures are addressed to a popular 

 audience, we ought not, perhaps, to object to the fine 

 writing in which the author is prone to indulge. But if 

 his little book should come to a second edition (as we 

 hope it may), he might tone down the " beauties," and his 

 work be none the worse, but all the better for the process. 

 Especially would we advise him to expunge the absurd 

 and incoherent " Geological Dream on Skiddaw," and 

 substitute for it a simple and intelligible summary, such 

 as we are sure he is quite capable of giving. The illus- 

 trations are unequal ; none of them are very creditable 

 works of art, and some are so smudgy as to be almost 

 illegible ; but for the most part they serve their purpose. 



J. G. 



LETTERS TO THE EDITOR 



[ 77c- Editor does not hold himselj responsible for opinions expressed 

 l,y his correspondents. No notice is taken of anonymous 

 commun ications. ] 



London University Examinations 

 Mr. Christopher Heath, in his Introductory Address at 

 University College, puts forward the following question, set in 

 the Preliminary School Examination, in support of his remark- 

 able statement that Mechanical and Natural Philosophy have 

 little to do with Medicine : — 



" Calculate the quantity of heat lost per hour from each square 

 metre of the surface of an iron steam boiler O'S centimetres in 

 thickness, when the temperature of the inner surface of the boiler 

 is 120" and that of the outer surface iigi"; the coefficient of con- 

 ductivity of iron being ii'S" (referred to 1 cm. as unit of length, 

 I min. as unit of time, and the quantity of heat required to raise 

 the temperature of I gramme of water from 0° to 1° c. as unit of 

 heat). ^ „ . 



' \Solutii)n : A difference of temperature of 1 in a thickness of i 

 cm. of iron will give a loss of irs" in I min. from a surface of i 

 sq. centimetre." 



I!ut a difference of 1° in the thickness 0-8 cm. is at 

 the rate of .'. -;- o'S = f° in the thickness of I cm. Hence 

 the loss in I "min. from I sq. centimetre is 11-5 x f = 7-1875. 

 Hence the loss in the same time from I sq. metre is 71875 units. 

 The loss of heat per hour will now be evident. 



Now this is what Mr. Heath designates as a problem on steam 

 boilers which a medical man can never want to solve ; would he say 

 that it is entirely foreign to the subject, and expect any member of 

 Senate or Convocation to bear him out, if the examiners inquired 

 how much heat a man would lose through a blanket or through a 

 se.ilskin coat 08 cm. in thickness, &c. ? Vet the question is the 

 same, and the iron jacket of the boiler or the sealskin coat are 

 only accidents. Should not a medical student have some idea of 

 the relation between the surface temperature of the body, the 

 quantity of heat passing away from it, and the amount of heat 

 generated in the body by the food given to a patient ? Is the pro- 

 duction of heat in the human body by the consumption of food 

 c irried on on principles so entirely different from those of the produc- 

 tion ot steam in a boiler that a medical student can afford to be igno- 

 rant of and to despise the simplest principles of heat, and to be 

 unable to answer the mildest questions in that subject ? More- 

 over, is it so clearly shown that "the two learned professors 



have such singularly incorrect ideas as to the requirements of 

 medical students " when they ask a simple question as to the 

 loss of heat from a hot body ? It may be that Mr. Heath 

 passed his first M. B. examination before it was considered a 

 matter of importance to note the changes of temperature of the 

 body, or before the use of thermometers by the Faculty, and 

 that he regards those who are guided by such things in their 

 treatment of a patient as altogether Utopian in their ideas. 

 The above consideration of the question may perhaps be a suffi- 

 cient answer to the shallow statement of the editor of the 

 Lunc't, in support of Mr. Heath, that "the relation of the 

 question to medical requirements is absurd on the face of it." 



As regards the examiners, Mr. Heath is not quite correct in 

 his statement of facts, for the present examineis are not the ex- 

 aminers on whom the sub-committee of Convocation reported 

 four years ago. With regard to the candidates who are rejected 

 at the preliminary scientific examinations, has it ever occurred 

 to the sub-committee of Convocation to inquire of the examiners 

 what standard is actually required for the Pass Examination ? 

 If they have not obtained this information from the examiners 

 themselves, their decisions can have very little weight, for they 

 cannot be in a position to judge whether it is from the high 

 standard set by the examiners or from the bad quality of the 

 work that so many are rejected. 



What stronger evidence could be adduced of the great value 

 of the Preliminary .Scientific Examination than the report of 

 this Committee that " it has tended to give prominence to theo- 

 retical and scientific knowledge," seeing that it is in consequence 

 of such knowledge that medical science has advanced with such 

 rapid strides, and that in many cases the whole course of medical 

 treatment has been changed. 



The pages of the number of the Lancet in which Mr. Heath's 

 lecture is contained, show clearly that to tlie surgeon, as well as 

 to the doctor, a knowledge of mechanical as well as natural 

 philosophy is of the first importance. Take, for instance, the 

 case reported on page 490 of that journal. 



How natural for a man who understands the laws of (pressure 

 of air, to apply the cupping-glass for the elevation of depressed 

 cranial bone, in place of an operation which kills in seventy-five 

 cases out of a hundred ! Can a surgeon dare to be ignorant of 

 these laws, when the consequences of neglecting them may be so 

 disastrous 



It is satisfactory to find, on turning to other medical schools, 

 that it is not the general opinion that the study of Natural Philo- 

 sophy may be neglected, but rather that "it is matter for regret 

 that more prominence is not given to Physical Science ;" for " it 

 is in Physics that we find the explanation of a great mass of 

 medical phenomena ; and to the student who has not attained 

 considerable proficiency in that science, many of these pheno- 

 mena must be unintelligible." 



Such being the case, the student will readily see that it will 

 be for his best interests, and will best promote his future useful- 

 ness as an intelligent medical man, to acquire a thorough know- 

 ledge of the first principles of Mechanical and Natural Philo- 

 sophy : in so doing, he will have the additional advantage that 

 he will not run such risk of being landed among those who are 

 rejected at the examinations of the University of London, and 

 that not by a severe examiner, but through the ill-advice of 

 which he has been the victim. W. G. Adams 



Physical Laboratory, King's College, Oct. 19 



Solar Spectroscope Observations 



In Nature of the 17th inst. there appear letters from CoL 

 Tennant and Mr. Capron, who seem to doubt that the solar pro- 

 minences can be seen in England with the facility described by 

 Capt. Herschel in India. I might almost apply Capt. Herschel's 

 words to my own experience last month. With a seven-prism 

 direct-vision spectroscope ofBrowning (open slit) attached to a 2\ 

 inch glass mounted on a drawing-room stand, not only the bright 

 lines, but the forms of the prominences, could be plainly seen and 

 were sketched. Of course there were many cloudy days which 

 prevented observations, and there would be many more such in 

 England than in India ; but it does not re(]uire exceptionally fine 

 weather, only a great deal of practice. Experience only will tell 

 the exact distance at which the slit must be from the sun's hmit, 

 and the slightest movement will either put the prominence out of 

 the field or swamp it «ith a flood of light. 



Uackheath, Oct. iS J, P. Maclkar 



