LITERARY NOTICES. 



133 



and the special hurtful resistances to motion, 

 the calculations of which have hitherto been 

 confined to the analytical method. No meth- 

 od being known to the author by which the 

 frictional resistances and efficiency of any 

 desired mechanism can be graphically deter- 

 mined, he has endeavored, in his lectures 

 before the polytechnic schools of Aix-la- 

 Chapelle, to show the relations existing be- 

 tween the forces in mechanism in a simpler 

 form than that offered by the analytical 

 method. The present treatise, which the 

 translator characterizes as containing "al- 

 most discoveries " on the subject, has grown 

 out of that endeavor. 



Compressed Gcn-Cotto.v for Military Use. 

 Translated from the German of Max ton 

 FoRSTER. New York : D. Van Nostrand. 

 Pp. 164. Price, 50 cents. 



Here ton Forster's practical manual on 

 the application of gun-cotton, which rests 

 largely upon the evidence of more or less 

 extensive experiments performed in Ger- 

 many, is preceded by an account of the 

 manufacture, properties, and uses of mod- 

 ern gun-cotton, by Lieutenant John P. 

 Wisscr, of the United States Army. 



Synopsis of the North American Syrphid.e 

 (Bulletin of the United States National 

 Museum, No. 31). By Samuel W. Wil- 

 LiSTON. Washington : Government Print- 

 ing-Office. Pp. 335. 



The family of Syrpliidm is one of the 

 most extensive in the order of Diptera. 

 "They contain among them many of the 

 brightest-colored flies, and numerous speci- 

 mens are sure to appear in every general 

 collection of insects. None are injurious in 

 their habits to man's economy, and many 

 of them are very beneficial." To be more 

 definite in popular description — " they are 

 flower-flies, and feed upon honey and pol- 

 len. They are observed on blossoms of 

 sweet-smelling, melliferous plants, such as 

 the Hymenoptera prefer ; and patches in 

 bloom of blackberry {Ruhui^, wild-cherry 

 {Prmius), dogwood {Cornus), Canada thistle 

 (CJrs?Mm), and elderberry (Sambucus), will 

 always be sure to reward the patience of the 

 collector. Some species, as those of Si/ritta, 

 Spivrnphoria, Mesograpta^ etc., will be seen 

 wherever there are blossoms. Species of the 

 last, especially, are very abundant about corn- 



fields when the plants are in blossom, and 

 will frequently alight upon one's hands ; 

 these ' sweat-flies ' are feared by not a few 

 persons, under the belief that they will 

 'sting.' All are sunshine-loving, and will 

 rarely be found except in the middle of 

 bright, unclouded days." About three hun- 

 dred species are described in this volume 

 from the region north of Mexico, in such a 

 way that the author hopes that even the 

 non-entomological student, with a little ex- 

 ertion, may be able to identify them. 



The Use of Electricity in Gynecological 

 Practice. Bv George J. Engelmann, 

 M. D., St. Louis. 



Dr. Engelmann believes that electricity 

 is a valuable agent in treatment, which had, 

 however, in his practice failed to give uni- 

 formly satisfactory results. lie set himself 

 to work to investigate the causes of the di- 

 versity in the efficiency of its application, 

 and publishes his experiments and the re- 

 sults of them in the present paper. His 

 decided success — in the treatment of pelvic 

 disorders — in the past year, "no longer 

 accidental, but the result of method " — ^haa 

 convinced him of the value of the remedy, 

 which he is assured, when fully developed, 

 will assume prominence. Its success and 

 general adoption, he believes, depends upon 

 precision and uniformity of measure and 

 record ; and he has given here, as a contri- 

 bution to those factors, his own system, 

 which includes the milli-ampere intensity 

 of the current; size of electrodes for calcu- 

 lation of density ; time of application, for 

 calculation of quantity ; resistance of the 

 tissues in ohms when such resistance was 

 unusual, or when an explanation of the in- 

 tensity of the current seemed called for. 



The City Government of St. Lodis. By 

 Marshall S. Snow. Baltimore : N. Mur- 

 ray. Pp. 40. Price, 25 cents. 



This monograph is one of the Johns Hop- 

 kins " University Studies in Historical and 

 Political Science." The "Studies" are now 

 in their fifth scries, which is especially de- 

 voted to the subjects of municipal govern- 

 ment and economics. The history of St. 

 Louis is given from its foundation in 1764, 

 with the various steps of its growth as an 

 infant settlement, a community, a munici- 



