72 REPORT OF THE SECRETARY. 



"11. Northern countries add to this cause of superiority, which they owe to the 

 constitution of their atmosphere, another, which is due to their geographical posi- 

 tion, namely, that the actinic effect of the sun increases more rabidly than the 

 duration of its presence ahove the horizon. The very long days of the north dur- 

 ing the period of vegetation are, therefore, in their actinic effect more active than 

 an equal numher of days in our temperate regions, and we can thus explain the par- 

 ticularly intense rate of the progress which vegetation makes in the vicinity of the 

 polar circle. . 



"12. This increase of sensitiveness which oxalic acid experiences in the sun does 

 not cease when the light begins to fade, and may continue several days. Hence fol- 

 lows a conclusion which may also be applied to our temperate regions. This is that 

 the actinic effect of a number of fine days in succession increases more rapidly than 

 its duration, and also that the effect of a fine morning is not lost by a dark and 

 cloudy evening. 



"13. We must therefore give up the hope of finding, in the duration of a day or 

 of solar action, a measure of its effects, and meteorological instruments which 

 accept such a propoi-tionality are to be rejected. 



"14. The importance of these actinic phenomena in the general economy of the 

 world is great enough to make it necessary that we should approach the investiga- 

 tion by appropriate means." 



II. SMITHSONIAN MISCELLANEOUS COLLECTIONS. 



The series of Miscellaneous Collections now includes 36 completed volumes, 

 embracing 173 distinct papers, besides parts of 4 additional volumes. The following 

 were published during the past fiscal year : 



No. 1035. Mountain Observatories in America and Europe, by Edward S. Holden, 

 director of the Lick Observatory. (Part of Vol. XXXVII of Smithsonian Miscella- 

 neous Collections.) Octavo pamphlet of vi, 77 pages, with 24 full page illustrations. 



In this paper Professor Holden describes the conditions of good vision at moun- 

 tain stations all over the globe, and makes a short study of the high-level observa- 

 tories in this country and Europe. The main scientific and practical conclusions to 

 be drawn from the facts presented are stated by Professor Holden as follows: 



"Briefly they show the necessity for a careful examination of the sites proposed 

 for an astronomical (or meteorological) observatory before a final choice is made. 

 They prove that while some mountain stations present great advantages for astro- 

 nomical and astrojihysical observatories, this is by no means the case for all. And 

 they point out that the more frequent use of balloons, etc., in meteorology is likely 

 to result in a rapid advance in our knowledge of the physics of the atmosphere, and 

 to do away, in a great degree, with the need for permanent meteorological stations 

 at high levels. 



"It ajjpears that different researches require different conditions. All would be 

 best done at a station where both steadiness and transparencv were absolute. But 

 some can be very well performed under less perfect conditions. If one is searching 

 for the site for a new observatory, both conditions should be insisted upon; if one 

 is planning work at a station already established, the work should be chosen so that 

 it can be well done under existing conditions. 



"None of these (and other) obvious conclusions are new. The mass of evidence 

 will, however, bring new conviction even to those most familiar with it; and it may 

 serve as a check on the wasteful expenditure of public and private eudowinents. 

 The subsidies to science, great as they are, thanks to the generosity of governments 

 and of individuals, must be carefully husbanded if we are to exploit its entire 

 domain, which is enlarging day by day." 



No. 1037. Methods for the Determination of Organic Matter in Air, by David 

 Hendricks Bergey, B. S., M. D., of the University of Pennsylvania. (Part of Vol. 

 XXXIX of Smithsonian Miscellaneous Collections.) Octavo pamphlet of i, 28 pages, 

 with 3 text figures. 



The difficulties that were encountered in estimating the quantity of organic mat- 

 ter in expired air, while conducting the research on the Composition of Expired Air 

 and its Effects upon Animal Life, are said by Dr. Bergey to have demonstrated the 

 fact that some of the methods in use were unsatisfactory. He reviews various 

 forms of apparatus used by foreign and American investigators, and concludes as 

 follows : 



"1. The quantity of organic matter bears an intimate relation to the amount of 

 dust floating in the air. It is probable that the gaseous organic matter forms but 

 an exceedingly small proportion of the total organic matter. 



