204 



SCIENCE. 



BOOKS RECEIVED. 



Compendium of Microscopical Technology ; A 

 guide to Physicians and Students in the use of the Mi- 

 croscope, and in the preparation of Histological and 

 Pathological specimens. By Carl Seiler, M. D. 

 Published by D. G. Brinton, Philadelphia, 1881. 

 The author of this work has a high reputation for pre- 

 paring mounted specimens for Microscopical study, and 

 therein gives short and clear descriptions of his own 

 methods, which have given such satisfactory results. The 

 reader is, therefore, not perplexed by being instructed in 

 the various methods suggested by many authorities, but 

 a clear line of conduct is indicated for him by Dr. Seiler, 

 which may be relied on as being satisfactory. 



The work is written for medical students, and for that 

 reason the usual subject matter found in Manuals of 

 Microscopy is altogether omitted, neither are descriptions 

 given of tissues, and the student is referred for histological 

 details to works devoted to histology. 



Without intending to cast any reflection on the body 

 of the work, we are inclined to consider the appendix the 

 most valuable part of Dr. Seiler's book. In it the author 

 presents a short, concise, and, at the same time, compre- 

 hensive classification of the more common tumors and 

 other neoplasms in tabular form ; these, indeed, will be wel- 

 come to the student of pathological histology. The author 

 claims to have exercised great care in its compilation, and 

 to have introduced all the accepted modern views on the 

 subject, so as to bring it up to the standard of the present 

 time. 



Popular Lectures on Scientific Subjects. By 



H. Helmholtz, Professor of Physics in the Univer- 

 sity of Berlin. Translated by E. Atkinson, Ph. D., 

 F. C. S. Second Series. D. Appleton & Co. New 

 York, 1 881. 



The present volume presents a series of addresses and 

 lectures delivered by Professor Helmholtz during a per- 

 iod of six years, from 1871 to 1877. The contents show 

 that the following subjects are treated : 



I. An address delivered before the Leibnitz meeting of 

 the Academy of Sciences, 1870. In memory of Gustav 

 Magnus. 



2. A lecture on the Origin and Significance of Geo- 

 metrical Axioms, delivered at Heidelberg, 1870. 



3. The substance of a series of lectures on the relation 

 of optics to painting, delivered at Cologne, Berlin and 

 Bonn. 



4. Lecture on the Origin of the Planetary System, de- 

 livered in 1 87 1. 



5. A*n address delivered in 1877, on the Anniversary of 

 the foundation of the Institute for the Education of Army 

 Surgeons : or, Thought in Medicine. 



Perhaps the only popular paper in the series is that 

 "On the Origin of the Planetary System," in which the 

 various hypotheses connected with the subject are ex- 

 plained in simple and familiar language. Professor 

 Helmholtz appears to have handled this subject in a 

 manner which must have been a source of delight to a 

 mixed audience. Touching on extinct suns he ex- 

 plained that a time would arrive when our own sun 

 would cease to develop the heat which is a source of vi- 

 tality to this earth. But he explained that 17,000,000 

 of years would lapse before this " intensity of sunshine, 

 would be diminished, and that circumstances may even 

 prolong this period." 



Looking forward to such a period when our sun shall 

 be extinguished, Professor Holmholtz observes that con- 

 sidering the wonderful adaptability to the conditions of 

 life which all organisms possess, who knows to whit 

 degree of perfection our posterity will have developed in 

 17,000,000 of years, and whether our fossilized bones 

 will not seem to them as monstrous as those of Ichthyo- 

 saurus now do ; and whether they, adjusted for a more 

 sensitive state of equilibrium, will not consider the ex- 



tremes of temperature, within which we now exist, to be 

 just as violent and -destructive as those of the older 

 geological times appear to us ? Yea, even if sun and 

 earth should solidify and become motionless, who could 

 say what new worlds would not be ready to develop life ? 

 Meteoric stones sometimes contain hydro-carbons ; the 

 light of the heads of comets exhibits a spectrum 

 which is most like that of the electrical light in gases 

 containing hydrogen and carbon. But carbon is the 

 element, which is characteristic of organic compounds, 

 from which living bodies are built up. Who knows 

 whether these bodies, which everywhere swarm 

 through space, do not scatter germs of life, wherever 

 there is a new world, which has become capable of giv- 

 ing place to organic bodies? And this life we might 

 perhaps consider as allied to ours in its primitive germ, 

 however different might be the form which it would 

 assume in adapting itself to its new dwelling place. 



Probably the lectures " On the Relation of Optics to 

 Painting " and the address "On Thought in Medicine" are 

 the most valuable productions of Professor Helmholtz to 

 be found in this volume, and as space for their proper 

 examination cannot be used in this notice, references 

 will be again made to them on another occasion. 



This work should find a place in every library of 

 standard works of Literature. 



A most successful experiment in theatre illumination 

 was tried on March 30 and 31, at the Athenaeum of the Rue 

 des Martyrs, Paris, with the Werdermann incandescent 

 light. The peculiarity of it is that it can be graduated at 

 will for scenic effects, either by introducing resistance coils 

 or varying the velocity of the Gramme machine. 



Effect of Temperature upon the Electrical Re- 

 sistance of Selenium. — Mr. Shelford Bidwell, in the 

 Pliilosophical Magazine for April, gives an account of some 

 experiments made on the above subject. He says : "The 

 room being 14° Centigrade, a selenium cell was immersed 

 in turpentine at 8° C. There was a great and sudden fall 

 in the resistance. The temperature was then gradually 

 raised. In passing from 8° to 24° the resistance steadily 

 increased ; from 24 upwards it rapidly diminished. For 

 this cell, therefore, the resistance is greatest at 24 C. Five 

 other cells were afterwards submitted to the same operation, 

 and their resistance was found to be greatest at tempera- 

 tures of 23 , 14 , 30 , 25°, and 22° respectively." 



Electric Transmission of Force for Working 

 Cranks. — According to E. Hospitalier, the use of hy- 

 draulic pressure for the transmission of the power required 

 in working cranes in docks, involves a loss which, in some 

 cases, ma)' reach 88 per cent. This evil is entirely obviated, 

 in addition to a great simplification of the entire plant, by 

 means of electric transmission of power, which enables the 

 original steam power to be fully utilised even when the 

 crane is raising much less than its maximum load. If we 

 reduce the loading of a crane the electro-magnetic machine 

 which drives it will have less work to do, and will revolve 

 more rapidly, and the stronger counter-currents thus pro- 

 duced will react upon the dynamo-electric machine in such 

 a manner that there is a less current produced, and a less 

 demand is made upon the steam-power. The only question 

 is, how the current is to be divided into several unequal 

 branches capable of being varied in strength at any mo- 

 ment. — La Lumiere Electrique. 



On the Stationary Electric Current in Conductive 

 Surfaces, and on the Galvanic Resistance of Psilome- 

 LAN. — Hugo Meyer, in the first portion of this memoir, dis- 

 cusses the ramification of the current, and the calculation 

 of the resistance of flat plates. The experimental results 

 agree with calculation. In the second part the author's ex- 

 perimental results agree with calculation. In the second 

 part the author examines the resistance of thin plates of 

 psilomelan, and obtains results antagonistic to those of 

 Braun, who found the resistance decrease under the in- 

 fluence of an induction current. 



