SCIENCE.dropped Professor Mayor's name from the titlepage, although ae-knowledging his indebtedness to that gentleman's book. The dis-tinctive features of the work as now presented consist in its- building-up a boy's knowledge of Greek upon the foundation ofhis knowledge of English and Latin," and in the fact that " noGreek words have been used in the earlier part of the hook exceptsueh as have connections either in English or Latin."

-Among the recent publications received from the UnitedStates Coast and Geodetic Survey Office is " Appendix No. 8, Re-port for 1888 (90 pp. sketch), entitled Geodesy. GeographicalPositions in the State of Connecticut. Prepared for publication byCharles A. Schott, assistant." This collection of geographical po-sitions, and of geodetic data resulting, is iiade in continuation ofthe scheme of publishing the results in those States where thetield-work of the triangulation is substantially completed, andwhere the triangulation could be made to rest on the standarddata of the survey.

-An interesting paper by Professor von Hofmann, upon thefdissociation of carbon dioxide gas into carbon nmonoxide and oxy-gen by means of the electric spark, is referred to in Nature ofDec. 4. Dalton and Henry long ago showed that carbon dioxide,although formed by exploding a mixture of two volumes of car-bon mnonoxide with one volume of oxygen by the passage of anelectric spark, is again partially decomposed into carbon tnonox-ide and oxygen by the continued passage of the spark. This dis-sociation, however, is very slow, and usually incomplete. Hof-mant and Buff, in the course of their well-known work upongaseous re-actions, further showedl that " the electric spark passesthrough carbon dioxide with a violet glow, producing at first arapid increase in the volume, which, however, becomes less andless marked until at the expiration of about half an hour the sep-arated carbon rnonoxide and oxygen recombine with a sudden ex-plosion, the re-formed carbon dioxide at once commencing to be

363again dissociated." Deville and Berthelot afterwards investigatedthe same phenomena, and also found that the re-action was nevercomplete, proceeding only until about 28 or 29 per cent of thecarbon dioxide was decomposed, but they never observed any ex-plosive recombination as described by Hofmann and Buff. Pro-fessor Hofmann has therefore determined the exact conditions underwhich the explosive recomnbination occurs. It certainly appearssomewhat remarkable that the same spark can effect both disso-ciation and recombination; yet such, within the limits describedin the memioir, is an actual fact. The first essential point to beobserved is the length of path of the spark. The most suitabledistance apart of the platinum terminals appears to be betweentwo and a half and three millimetres, and Professor Hofmaninadvises the use of adjustable terminals rather than the ordinaryplatinum vrires fused into the side of the eudiometer. A Leydenjar in the circuit renders the occurrence of periodical explosionsmore certain. The spark should also pass at about a quarter theheight of the gas column, instead of, as usual, near the top. Thecurrent itself, moreover, should not be too strong: that from twoBunsen cells and only a moderate sized Ruhmkorff coil is quitesufficient, and yields the best results. It is also preferable to usea volume of carbon dioxide, previously dried over oil of vitriol,not exceeding ten cubic centimetres at a pressure of 650-700 mil-limetres: eight cubic centimetres give excellent results. Underthese conditions, the first explosion usually occurs in fromn fifteento twenty minutes, and sometimes earlier. The flame commnencesin the neighborhood of the spark, and then perceptibly spreadsthrougli the whole length of the gas column. It is colored bluein the first explosion, and green in the succeeding ones, owing tothe volatilization of a litae mnercury vapor. The second and sulC-ceeding explosions occur after shorter intervals than the first.This experiment is certainly one of the mrost interesting in all therange of dissociation phenornena; and full details, with drawingsof the apparatus, are given by Professor Hofmann in his memoir,

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364 SCIENCE.CALENDAR OF SOCIETIES. JefUST PUBLISHED.

Philosophical Society, Washington. HOUSEHOLD HYGIENE.By MARY TAYLOR BISSELL, M.D., NEw YORK.

Dec. . AnnualReportsof1the5Treaurer cents.and Secretaries, and election of officers for "This little volume has been compiled with thethe year 1891. hope that the housekeeper of to-day may find in

its pages a fevr definite and simple suggestionsThe Anthropological Society, Washing- regarding sanitary house-building and house-

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Dec. 16 -Robert Fletcher, The Vigor andwhose enforcement les tephyicaExpressiveness of Older English. promise of family life " (author's preface).

TIME RELATIONS OF MEN-Wants. TAL PHENOMENA.

Any ierson seekisga osition for which he,ia'saai- By JOSEPH JASTROW, PROFESSOR OF PSYCHOL-edty hisscietifctainseeni, or yfierson sething OGY AT TIlE UNIVERSITY OF WISCONSIN.comer one fo fil a positiown ef this character, be it thatof a teacher ef/sciecer chemist, drangisman, or what 12'. 50 cents.not, mnay hats, the ' iVant' inserted snder chic headFRgEx: OF COST, if he satisfies the psto'iser of the snit- It is only within very recent years that thisai'e character e0/his apicration. Anyperonreneokin department of research has been cultivated; andinformation o# any scientific eestion, the afddress ofany scientmficman, or who can any way asthisco- it is natural that the results of diffetent workers,nrma for a pfsiiose consonant ovith the nature of the involving variations in method and design,paper, is cordially invitedito do so. should show points of difference. In spite of

llANTED.-A young man wishes a position as in- these it seems possible to present a systematicVWV structor in the sciences in some school or sketch of what has been done, with due referencecollege. Chemistry a specialty. Would like to hear to the ultimate goal as well as to the many gapsof some position with a private or manufacturingchemist, in which his knowledge of ehemistry would still to be filled.help him. Address E. E. TOWNE, B.A., 272 Worth-ington St., Springfleld, MSass.11n unp 17Tf t mi-gn St. Springfield,..as11. D. C. HODOES, 47 Lafayette Place,IWANTED.-An ExploriExExpedition, backed by NEW YORK.VVit11i R1 Wi~~~lLh lafntitn A lcYi allsh *t* .uO,,,,',, uei3rac,s. 11 as anna fnlu, sue Loris-

ith Northwest Territory the coming year to be goneone or two seasons. A scientist or two will miorethan likely be taken along. Applications from,suchwill be gladly received and carefully considered.To assist in making these applications the comnman-der would say tbat he cot siders a full practicalknowledge of ilineralogy and geology necessary, andif the applicant can add the duties of botauist. eth-nologist, or any other of the sciences, aiid photog-rapty. sketching, medicine and surgery, or otherusefel arts for exploring, it will add to the chancesof neung selected. Applicants must be physicallyperfect, and ought to be about mediui age. One oftherse scientists wvill be the second in command ofthe party. Any credentials forwarded for consider-atton wili be returned, if reqested, after considera-tion. Address "ALASKA,' care olf Science.

1WANTED.-There being a considerable annualVVineome for the purchase of books for the Mu,seum efterence Library of Iowa College, it is de-sirable to have at hand any and all circulars, spedi-men sheets, catalogues, etc., of all works on NaturalHistory in general, both foreign and domhestic.Circulars of museum supplies, apparatus, etc., etc.,desired also. State temas. Address ERWIN H.BARBOUB, Box 128a, Grinnell, Iowa.

IJANTED.-A situation as Analytical Chemist isW desired by the assistant of the late notedscientist, Dr. Cook, during his 15 years survev of theState of New Jersey. Hi hest testirnonials furnished. Address Prof. gDWIN H. BOGARDCS,New Brunswick, P, 0. Box 224, care Prof. F. CVan Dyck,

OTJLD some one inform me what the ingredientsnd orin of asphalt as used for street-pavinganldgathered at Trinidad are? Also how ga here

and shipped by natives, and mode of refining by theWarren-Scharf Co. of Nee, York and the Barber Co.of Washington? G. KNIPEtH, 28 Gunn Block, GrandRapids, Mich.

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contailing a complete list of the manufactures and pro-ducts of the U. S., and address of first hands, cost $6.David R, Lewis, Saybrook, 111.For exchange-Nice specimens of Unios alatus, trigo-

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