520 



SCIENCE. 



[Vol. IV., No. 96. 



of varieties established, agricultural botany 

 may prove of much value to the farmer, gar- 

 dener, and seedsman. Until then it belongs 

 in the categoiy of hopeful experiments. 



The reader will find in it an account of Mr. 

 Hopkinson's modification of the Edison d} T na- 

 mo, and also a description of the latest modi- 

 fications of the Giilcher machine, and also of 

 the Thomson-Ferranti machine. 



MINOR BOOK NOTICES. 



A treatise on the adjustment of observations, with appli- 

 cations to geodetic work and other measures of pre- 

 cision. By T. W. Wright, B.A., late assistant 

 engineer LI. S. lake-survey. New York, Van 

 Noslrand, 1884. 437 p. 8°. 



The student of the method of least squares 

 often fails to grasp the true meaning and sig- 

 nificance of the method, from the want of illus- 

 tration and well-chosen applications . The chief 

 merit of Mr. Wright's book is in the collection 

 of examples which have been drawn from the 

 records of actual work in which the author has 

 been engaged. Besides the application of the 

 methods of least squares to the results of 

 triangulation and of levelling, a chapter is 

 devoted to these methods in relation to line- 

 measures in general, and to the calibration of 

 thermometers. 



There are some observers who are tempted 

 to believe in the infallibility of certain criteria 

 proposed by different writers for the determi- 

 nation of the weight of observations. There 

 are others who reject the mathematical criteria, 

 and prefer graphical methods as guides to a 

 correct judgment. Mr. Wright is one of those 

 who prefer to look at observations from the 

 practical observer's point of view. His treatise 

 will therefore be of interest to the mathemati- 

 cian who desires to frame criteria which will 

 represent more closely the results of experience, 

 and will prove of great utility to the practical 

 man. 



Recent progress in dynamo-electric machines, being a 

 supplement to dynamo-electric machinery . By Prof. 

 Sylvanus P. Thompson. New York, Van Nos- 

 trand, 1884. (Van Nostrand sc. ser., No. 75.) 

 113 p., illustr. 24 c . 



The writers who rapidly assimilate the ad- 

 vances in electrical engineering, and present 

 their knowledge to the public in an intelligible 

 way, are doing very useful work. The treatises 

 of Professor Thompson are increasing upon 

 the electrician's book-shelf. The time has not 

 arrived for a standard treatise on electrical en- 

 gineering, on account of the rapid changes and 

 development of the subject. Until we can 

 have such a standard treatise, we must rely 

 upon brochures like this latest production of 

 Professor Thompson. 



Wonders and curiosities of the railway; or, Stories 

 of the locomotive in every land. By William 

 Sloane Kennedy. Chicago, Griggs, 1884. 

 16 + 254 p. 12°. 



One is a little startled, on opening this book, 

 to find mentioned the " huge, ample-shadowed 

 foundry ; the peculiar fragrance of burnt earth 

 and iron ; . . . the boy controlling the huge 

 steam-hammer; . . . and, finally, the great crane 

 that lifts up the monster in chains, and carries 

 it to the doorway, and sets it down in all the 

 resplendence of its polish and paint, read} T to 

 begin its thirty years of toil," with nothing 

 predicated of them ; but is relieved immedi- 

 ately by the statement that ' this is the build- 

 ing of the locomotive.' This introductory 

 chapter, in which ' our old Homeric poet 

 Whitman ' receives praise, and which may 

 have been written by him, should not, however, 

 deter the reader from going deeper into the 

 book. From chapter ii. on, the writer tells 

 the anecdotes he has collected in regard to 

 the railwa} T , and has succeeded in bringing 

 together a most entertaining collection. The 

 account given of the Quincy railway must 

 change the impression that many have of that 

 so-called ' first American railroad.' The chap- 

 ter on the ' locomotive in slippers ' is devoted 

 to the history of the railway in the east, and at 

 times is especially amusing. The author also 

 touches upon the ' vertical railwa}^ ' (the eleva- 

 tor) , upon the various mountain railways, and 

 upon the recent attempts to use electricity as 

 a transmitter of power. 



NOTES AND NEWS. 



A. conference to formulate plans for the syste- 

 matic observation and discussion of earthquakes was 

 recently held in the rooms of the U. S. geological 

 survey in Washington, at which there were present 

 Messrs. Powell, Dutton, and Gilbert, of the survey, 

 Abbe and Marvin of the signal-service, Paul of the 

 naval observatory, Rockwood of Princeton, and Davis 

 of Harvard college. It was decided that three classes 

 of observations should be attempted; the first class 

 consisting of those made by self-registering seismom- 

 eters of approved pattern, upon which Messrs. Paul, 

 Rock wood, and Marvin are to report at an early date. 

 The second-class observations will be chiefly to deter- 

 mine the time of shock, probably by means of a 



