May 3, 1895.] 



SCIENCE. 



481 



very moderate number of pages of print, 

 are a crystallization of all the known facts. 

 Especially may be mentioned the investiga- 

 tions of inequalities in the periods of these 

 bodies. AVhUe the number of these in- 

 equalities known in Schonfeld's time 

 amounted to onlj- about half a dozen. Chand- 

 ler has detected their existence in about 

 eighty other stars, and has deduced the 

 numerical laws in about fifty of them. This 

 will indicate, in one direction onh', how the 

 labor of caring for these objects is increasing. 



It would be unjust if. while alluding to 

 these important researches, no mention 

 were made of Mr. Chandler's ingenious and 

 successful device of a new form of instru- 

 ment for making that class of measure- 

 ments of position which had previously been 

 made bj- mei-idian instrument alone. Both 

 the instrument and the method were novel. 

 In the former, instead of a motion of rota- 

 tion, determined mechanicallj- bj' the pivots 

 of a horizontal axis, there was substituted 

 one about a vertical axis determined bj- 

 ■gravitative action of an instrument resting 

 in mercury. 



As to method, instead of a vertical plane 

 passing through the pole, which is the fun- 

 damental plane of reference for meridian in- 

 struments, there was substituted a horizon- 

 tal circle. The value possessed by such an 

 entirely diflerent method consists in substi- 

 tuting a totallj' difierent sort of observation, 

 and hence a ditlerent set of the sj^stematic 

 errors to which all observations are liable, 

 so that the combined results of the two 

 methods are likely to be freer from them 

 than those obtained by an adherence to a 

 single system of observation. In a memoir 

 of 222 pages Dr. Chandler develops the 

 theory of the instrument and method math- 

 ematically, and gives the result of its 

 practical use in observations made with it 

 for a year, and directed to various astro- 

 nomical problems. 



Although not mentioned as forming anv 



part of the grounds for the award of this 

 medal. Dr. Chandler's important labors for 

 many j'ears upon cometary orbits are well 

 known to astionomers. Casual mention 

 may be especiallj- made of his computations 

 relative to the principal component of 

 18S0Y, and the action of Jupiter in 1886 

 upou it, which led to a complete transforma- 

 tion of its orbit ; also the definite deter- 

 mination of the relative orbits of the sev- 

 eral components into which the comet be- 

 came separated in consequence of that dis- 

 turbance. 



The Trustees of the Watson Fund feel 

 that this brilliant series of investigations is 

 preeminently deserving of the highest rec- 

 ognition which can be given by the Nat- 

 ional Academy, and have therefore not hes- 

 itated in recommending the award of the 

 medal to Dr. Chandler. 



S. Newcomb. 



B. A. Gould. 



A. Hall. 



SUMMARY OF COXCLUSIO.VS OF A REPORT BY 

 DR8. D. H. BERGEY, S. WEIR MITCHELL 

 AND J. S. BILLINGS UPON 'THE 

 COMPOSITION OF EXPIRED 

 AIR AND ITS EFFECTS 

 UPON ANIMAL LIEE.'* 

 1. The results olitained in this research 

 indicate that in air expired by healthy mice, 

 sparrows, rabbits, guinea pigs or men 

 there is no peculiar organic matter which 

 is poisonous to the animals mentioned 

 (excluding man), or which tends to pro- 

 duce in these animals any special form of 

 disease. The injurious eflects observed of 

 such air appeared to be due entirely to the 

 diminution of oxygen or the increase of 

 carbonic acid, or to a combination of these 

 two factors. They also make it very im- 

 probable that the minute quantity of organic 



* Results of an investigation mode under the pro- 

 visions of tlic Hodffkin's Fund. Head before the Na- 

 tional .Vcademy of Sciences, .\pril IG, 189.5, by permis- 

 sion of the Secretarv of the Smithsonian Institution. 



