August 3, 1888.] 



SCIENCE. 



59 



Measures Service. As this is the result of the thermometric studies 

 pursued at the International Bureau for several years, it seems de- 

 sirable to give it ji wider publicity than is offered by the publica- 

 tions of that bureau alone, from which these statements have been 

 collected by me. 



The standard scale adopted is, by the wording of the resolution 

 "the centigrade scale of the hydrogen thermometer, having for its 

 fi.xed points the temperature of melting ice (o") and that of steam 

 (100°) of water boiling under a standard atmospheric pressure. 

 The hydrogen being taken under a manometric pressure of i metre 

 of mercury, i.e., '■f^^ = 1.3 158 times the standard atmospheric 

 pressure." The standard atmospheric pressure is that exerted by 

 a column of mercury (density = 13.596) 760 millimetres long at 0° 

 C, at the mean sea-level in latitude 45°. An increase of pressure 

 of one atmosphere lowers the melting point of ice about o''.oo8. 



All the thermometers used at the bureau are made of the same 

 kind of glass, the composition of which was found by chemical an- 

 alysis to be — 



Stem. Bulb. 



Silica 71.45 71.52 



Sulphuric acid (bOs) 0.74 0.72 



Chlorine - traces traces 



Aluminum ..26 ,.57 



Peroxide of iron 0.29 o 22 



Lime 14.52 14.55 



Soda II. 17 lO.Si 



Potassa 0.30 0.37 



Ma^esia traces traces 



Protoxide of manganese traces traces 



99.73 99.76 



The exclusive use of this glass has several advantages. 



1. The changes of the zero point are relatively very small, and 

 its depression due to increase of temperature is practically a recti- 

 linear function of the latter within the limits — io° + lOo". 



2. The thermometers are comparable among themselves, and it 

 was found practicable to establish a general formula for reducing 

 their indications to the standard hydrogen scale. A table of cor- 

 rections based on this formula is given below, but of course it is 

 applicable only to thermometers of this kind of glass. The reduc- 

 tion of the indications of mercurial thermometers to a gas ther- 

 mometer depends on the kind of gas used and on the glass of 

 which the mercurial thermometer is composed. 



7" hydrogen = ?" mercury + correction. 



O. H. TiTTMANN. 



Washington, D.C., July 27. 



Turner's Explorations in Alaska. 



It is with no small degree of satisfaction that naturalists are re- 

 garding the publications that are appearing from time to time from 

 the office of the Chief Signal Officer of the Army at Washington, 

 referring, as we do more particularly, to the reports made under the 

 auspices of that office by the Alaskan explorers. The last one of 

 these, very recently issued, is now before us, and presents in an ad- 

 mirable manner the results accomplished in that region by Mr. Lu- 

 cien M. Turner, during the years 1874 to 1881, who carried on his 

 explorations there under the direction of the Chief Signal Officer, 

 and in connection with the National Museum. 



Issued in the usual Government form, this quarto volume of some 

 225 pages, with its twenty-six plates, makes a ver)- handsome work. 

 It has been entitled ' Contributions to the Natural History of Alas- 

 ka.' and is the second of the series,— its author dividing its con- 

 tents into six parts for treatment. Of these, Part I. presents a very 

 short and concise general description of the regions explored, and 

 we learn that Mr. Turner was at various times stationed at Saint 



Michael's, Unalashka, the islands of Saint Paul and Alkha, at Altu, and 

 many other points of interest. Part II., occupying about forty pages 

 of the work, is devoted to meteorological observations, and presents 

 in a fairly-well digested manner, the author's labors in this direction, 

 and it is needless to add that the data here collated are not only of 

 interest but of great scientific value. In Parts IlI.-VI., inclusive, the 

 plants, fishes, birds, and mammals are dealt with, and in a very 

 thorough manner when we consider many of the difficulties the au- 

 thor was obliged to overcome. Perhaps the botany of the region 

 gained the least at Mr. Turner's hands, and it consists simply of his 

 field-notes, added to Rothrock's list of 1867, the author stating "in 

 this connection that of all great difficulties the most troublesome % 

 was to preserve the plants after 1 had collected them. The con- 

 stant moisture 6( the climate has frequently ruined my entire collec- 

 tion of a summer's work. All that remained after supposing the 

 plants were sufficiently dried would be a mass of mould and dry 

 edges of paper, this being apparently done in less than forty-eight 

 hours' time." 



A frog {Raita sylvatica ?) was the only reptile collected ; and at 

 Fort Yukon, just within the Arctic circle, this species is reported 

 to be quite plentiful. Some excellent work was accomplished in 

 ichthyology, and a number of species added, new to science, and 

 several rare forms collected. Fourteen beautiful plates of fish are 

 given, and one of a lamprey (A. aureus), and it would be not easy 

 to overestimate the interesting and valuable field-notes here pre- 

 sented. Habits, uses, geographical ranges, and other matters, are 

 treated with distinguished ability, and in this, much is due to the 

 assistance of Dr. Bean of the Smithsonian Institution. 



What we have just said in reference to the ichthyological part» 

 applies with more than equal force to the work done in ornithol- 

 ogy ; and to state the fact that no less than ten elegantly colored 

 plates of birds by Robert and John L. Ridgway are given, is equiv- 

 alent to saying to ornithologists and others, who may not yet have seen 

 the work, that a feast for their eyes is still before them. The whis- 

 kered auklet {S. pygmaus) is figured in full breeding plumage; 

 Turner's ptarmigan, male and female, are both given ; excellent fig- 

 ures of the Lapp and Hawk owls, and others of special interest. 

 Through the published field-notes much has been added to our 

 knowledge of the habits of many of these arctic bird forms. 



No mammals, unfortunately, are figured, and this part of the re- 

 port has evidently not received the attention it so justly deserves, 

 and in speaking of Cooper's shrew, our author evidently confuses 

 that diminutive insectivore with the rodents. The volume is com- 

 pleted by a very full and useful index, and Mr. Turner is to be con- 

 gratulated, not only upon the appearance of his work, but upon 

 the successful termination of his explorations and labors. 



Another volume by the same author is promised soon by the Sig- 

 nal Ofiice, also one from Mr. E. W. Nelson, upon the same region ;. 

 and finally General Greely's own report upon the Lady Franklin 

 Bay Expedition, which will be looked for with very general interests 



It is to be hoped that the government will appreciate more and 

 more such works and the reports thereon, and be induced to aid 

 and encourage them as much as possible. 



R. W. Shufeldt. 



Fort Wingate. N.Mex., July 22. 



The Use of the Microscope as a Practical Test for Oleomar- 

 garine. 



The act passed by Congress entitled " An Act defining butter, 

 also imposing a tax upon and regulating the manufacture, sale, im- 

 portation, and exportation of oleomargarine." approved .August 2, 

 18S6, commonly known as the ■ oleomargarine law." makes it the 

 duty of the Commissioner of Internal Revenue to prescribe all 

 needful regulations for carrying it into effect. 



From the ist of November. 1S86, when the law first went into 

 effect, to October, 1S87, one hundred and thirty-one samples of 

 substance supposed to be oleomargarine were submitted for the 

 decision of the commissioner under sections 14 and 15 of this act. 

 twenty-one of which proved on analysis to be oleomargarine, and 

 one hundred and ten were found to be butter. Most of these latter 

 were old and rancid. The ver)' prevalent idea that rancidity is the 

 most characteristic properly of oleomargarine may account for the 



