January 27, 1893.] 



SCIENCE. 



55 



It grows with great rapidity, in France reaching a height of 50 

 feet iQ 8 years. It is hardy in the milder parts of England. It 

 yields a valuable volatile oil, and it is said when combined with 

 thymol and other antiseptics to be efficacious in treatment of 

 scarlet fever and other infectious diseases, especially as an exter- 

 nal application. Fresh branches placed under the bed of phthisic 

 patients act as an antiseptic, a sedative, and a hypnotic. The 

 plant is also useful in subduing malarial efHuvia in fever dis- 

 tricts. 



We cannot go further into details, but commend the volume to 

 all botanists and horticulturists. Various indexes, of trees best 

 adapted for certain purposes, of genera referred to, of synonyms, 

 of vernacular names and of species best adapted to various re- 

 gions of the globe, add greatly to the value. The price of the 

 book is only five shillings. Joseph F. James. 



Washington, B.C., Jan. IS. 



A Text-Book of Least Squares. By Mansfield Mereiman. 6th 

 Ed. New York, J. Wiley & Sons. 1893. 198 p. 8». 



Tlieory of Errors and Method of Least Squares. By W. W. 

 Johnson. New York, J. Wiley & Sons. 1892. 174 p. 

 13°. 



We have here two excellent works, written by two able men, 

 and illustrating in an interesting manner those different views of 

 identical principles and methods which independent thinkers are 

 always able to exhibit, however old and well-worked tbe subject. 

 Professor Merriman wrote his first edition of this treatise in 1877, 

 with the purpose of presenting the facts and principles of this some- 

 what abstruse subject in such form as to make them easily compre- 

 hended by students and by engineers, in practice often less familiar 

 than the student with work underlying the higher mathematics. 

 That treatise, while successful, served nevertheless, to indicate 

 where still further improvement might be effected, and the present 

 is a re-written treatise, of which the major portion was prepared 



and printed in 1884, as a second edition. The sixth edition, now 

 before us, contains the same matter in substance, but with the 

 usual and unavoidable printers' and other errors, always found' 

 in first issues, removed, and some improvements introduced ia 

 the treatment of adjustments of two related quantities, and with 

 notes of interest appended. The book has become a standard' 

 work of reference, as well as a text-book, and needs no special' 

 commendation from us, other than the expression of full agree- 

 ment with the verdict of the purchasers and usei"s of five issues,, 

 who have made necessary this sixth edition. 



Professor Johnson has condensed his work into a smaller com- 

 pass than the preceding; but it is all the more rich and " meaty." 

 The author follows Gauss in the methods laid down in " Theoria 

 Motus Corporum Ccelestium " (Werke, VII,), and treats the "re- 

 duced observation equations" by the more explicit methods intro- 

 duced by Jordan ("Handbuch der Vermessungskunde," 1888)- 

 and later writers, including Oppolzer, to whom he goes for some 

 of the more important forms adopted in computations. The 

 book is systematic, logical in its sequence, and well illustrated 

 by carefully chosen examples in application. Appended are ta- 

 bles of values of the probability-integral and of powers and 

 roots. 



When a mathematician of eminence undertakes thus to provide a. 

 treatise upon a subject of importance, and compiles a text-book, for 

 young students, not only the youth who is thus provided with 

 a text-book but the whole world of observers employing such 

 methods become more indebted to him than to the less distinguished 

 and less talented man doing similar work; we have the assurance, 

 not only that the book will serve its purpose, but that it represents 

 the latest and best thought and labor of the time. This assurance 

 is worth much to teacher and pupil ; and it can hardly be doubted 

 that the use of this little treatise will extend beyond the limits of 

 the United States Naval Academy, where it was originally in- 

 tended by its author to be used, in his own classes. 



Bffspepsia 



Dr. T. H. Andrews, Jefferson 

 Medical College, Philadelphia, says of 



Horsford's Acid Phosphate. 



"A wonderful remedy which gave me 

 most gratifying results in the worst 

 forms of dyspepsia.*' 



It reaches various forms of 

 Dyspepsia that no other medi- 

 cine seems to touch, assisting 

 the weakened stomach, and 

 making the process of diges- 

 tion natural and easy. 



Descriptive pamphlet free on application to 

 Rumford Chemical Works, Providence, R. I. 



Beware of Substitutes and Imitations. 



For sale by all Druggists. 



Exchanges. 



[Freeof charge to aU, if ofsatisfactory character 

 Address N. D. C. Hodges, 874 Broadway, New York.l 



For sale or exchange. — T have a few copies of my 

 translation of " Strashurger's Manual of Vegetable 

 Histology, 1887,'' now out of print, which I will send 

 post-paid for $3 or for one dozen good slides illus- 

 trating plant or animal structure. Address A. B, 

 Hervey, St. Lawrence University, Canton, N. Y. 



The undersigned has the following specimens to 

 exchange for crystals of any eastern or foreign lo- 

 calities or Indian relics: tin ore, metacinnabarite, 

 stibnite, garnierite, calenanite, hanksite, ulexite, 

 rubellite, lepidolite,blue and green onyx, Cal. pine- 

 ite, aragonite on chalcedony, cinnabar, double re- 

 fracting spar, clear and clouded, and others. J. R. 

 Bush, care of General Delivery, Los Angeles, Cal. 



For sale or exchange. — A private cabinet of about 

 200 species of fossils, well distributed geologically 

 and geographically. Silurian, about 40; Devonian, 

 about 50; Carboniferous, about 80; others, about 30. 

 Frank S. Aby, State University, Iowa City, la. 



For exchange.— Minerals, fossils, F. W. shells, 

 land shells, native woods, ladian relics, two vols, 

 of Smithsonian reports, odd numbers of scientific 

 magazines, copper cents, etc., for good minerals 

 not in my collection, good arrow- and spear-heads 

 and natural history specimens of all kinds. Cor- 

 respondence solicited with list of duplicates. G. 

 E. Wells, Manhattan, Kan. 



For sale or suitable exchange.— A spectrometer 

 made by Fauth & Co., Washington, D. C., according 

 to the plan of Prof. C. A. Young. This instrument 

 is suitable for the most advanced investigations 

 and determinations. Cost originally S700 and has 

 been used but little. Will be disposed of at a con- 

 siderable reduction. Address Department of Phys- 

 ics, Ohio University, Athens, O. 



I will send British land and fresh-water shells in 

 return for those of America, any part, sent to me. 

 I have at present about fifty or sixty species, with 

 many varieties. W. A. Gain, Tuxford, Newark, 

 England. 



The Biological Department of Hamline University 

 desires to offer microscopic slides of animal tissues, 

 or whole animals, in exchange for first-class fossils. 

 Address correspondence to Henry L. Osborne, Ham- 

 line University, Hamline, Minn. 



Wa7its. 



WANTED.— American Journal of Conchology, 

 seven volumes. Parties having these for 

 sale will please address the undersigned, stating 

 condition and price. R.Ellsworth Call, Louisville, Ky.. 



A GRADUATE ENGINEER will give instruction, 

 evenings in geometry, trigonometry and sur- 

 veying, mechanics, physics, mechanical drawing 

 and general engineering construction. Five years' 

 experience in field and editorial work on engineer- 

 ing journal. References furnished. C. S. H., 102 

 Tribune Building, New York. 



WANTED.— By well- qualified and experienced, 

 science master and associate of the Royal 

 School of Mines, London, aged 26 (at present in 

 England), a mastership In technical college or uni- 

 versity for any of the following subjects: Engineer- 

 ing sciences, geology and mineralogy, physics, chem- 

 istry and metallurgy, etc.. etc. Can provide excel- 

 lent references and credentials. Apply, J. G., 17 

 Sussex St., Rochdale, England. 



A GRADUATE of the University of Pennsylvania 

 and a practical mineralogist of twenty years' 

 experience desires to give his services and a cabi- 

 net of 25,t'00 specimens, all named, with about the 

 same number of duplicates, in minerals, crystals, 

 rocks, gems, fossils, shells, archteological and ethno- 

 logical specimens and woods to any institution de- 

 siring a fine outfit for study. The owner will in- 

 crease the cabinet to 50,000 specimens in two years 

 and will act as curator. Correspondence solicited 

 from any scientific institution. J. W. Hortter, 

 M.D., Ph.D., San Francisco, Cal., General P. O. 

 Delivery. 



THE RADIOMETER. 



By DANIEL S. TROY. 

 This contains a discussion of the reasons 

 for their action and of the phenomena pre- 

 sented in Crookes' tubes. 



Price, postpaid, 50 cents. 



'Klndlij mention "Science" in n oni -a a ww 



writing to Advertisers. N. D. C. HODGES, 8(4 BrOadWay, N. Y. 



