572 



SCIENCE. 



|Vol. VII., No. 177 



of difficulty, but to so arrange the observatory that 

 the influence of the wind shall be either measured 

 and subtracted, or avoided altogether. Place the 

 barometer in an air-tight box, made partly of glass 

 for purposes of observation, and connect this box 

 by a tube with an opening on the roof so adjusted 

 that it shall always sustain the same relation to the 

 wind. It is possible that a form of opening can be 

 devised such that the wind will neither compress nor 

 dilate the air within the box ; but, if this cannot be 

 done, it is certainly possible, by a proper system of 

 experiments, to determine for a given arrangement 

 of aperture the proper correction to apply to the ba- 

 rometer-reading for each measured velocity of wind. 

 The matter should receive thorough investigation. 



G. K. Gilbert. 



Washington, June 19. 



I infer from Prof. John LeConte's letter in your 

 last issue (Science, vol. vii. p. 550) that he does not 

 feel entirely satisfied with the explanation I have 

 offered of the slight fluctuations of the barograph 

 observed at Blue Kill during high winds. He says, 

 " The observed facts are, that fluctuations of wind- 

 velocity correspond with fluctuations of air-pressure. 

 In some cases it may be difficult to decide which is 

 cause, and which is effect." In this case, the fact, 

 as stated in my last letter, that I cculd produce these 

 fluctuations at will by merely opening and closing a 

 hatchway in the top of the building, seems to me to 

 prove conclusively that the wind was the cause, and 

 the change in the pressure the effect. In regard to 

 his suggestion that a comparison should be made 

 between a barograph inside and one outside of the 

 building, I think, before satisfactory results could be 

 obtained, it would first have to be proven that the 

 wind in blowing across the top of the barometer 

 cistern, or at right angles to the crevices of such 

 cistern, would not have the same effect of lowering 

 the readings of the barometer outside as well as 

 inside of the building. 



Mr. E. B. Weston of Providence has informed me 

 that he has noticed during high winds small oscilla- 

 tions of his barograph, similar to those observed at 

 Blue Hill, and has prevented them by opening the 

 windows, so as to give a free draught of air. I 

 tried the same at Blue Hill during a late high wind, 

 and found that the oscillations, which at most were 

 slight, were reduced by it. 



In regard to those large differences between the 

 observed and estimated pressure on Mount Washing- 

 ton, referred to in my last as collected by Professor 

 Loomis, it is probable, that, in these extreme cases, 

 other causes than that suggested by me become 

 factors in the result ; such, for instance, as a lagging 

 of the time of minimum pressure at the top as com- 

 pared with the base, and a more violent cyclonic cir- 

 culation of the wind at that height, — causes which 

 have been suggested by Professor Loomis in his twen- 

 tieth paper (Amer. joum. sc., vol. xxviii. July, 1884). 



H. Helm Clayton. 



Blue Hill meteor, observ., June 19. 



A most extraordinary structure. 



Referring to P.Z.S. 1885, p. 908, pi. lxi. fig. 3, h, 

 where my amiable young: friend Dr. Shufeldt de- 

 scribes and figures the humerus of a humming-bird as 

 ' a most extraordinary structure,' I may be per- 

 mitted to suggest that some of the alleged 1 eccen- 

 tricities ' of this ' unique ' bone might seem less if he 



had not got the bone turned hind part before by one 

 of those strokes of genius which a prosaic world, 

 steeped in materialism, is slow to appreciate. 



A Theosophist. 



Smithsonian institution, 

 Washington, June 15. 



Aspects of the economic discussion. 



I have just read Professor Newcomb's article 

 (Science, vii. No. 176) on the new school of political 

 economy. It seems to me that the professor asks 

 for too much in the way of results from the new 

 school. As I understand it, this is simply a question 

 of methods. The new school professes the historical 

 method, as opposed to the deductive method of the 

 so-called orthodox school. If the historical method 

 is right, the results eventually arrived at will, nay 

 must, be right. But to stop them on their way as if 

 with a revolver, and demand a categorical statement 

 of their views on such disputed points as state inter- 

 ference before they are allowed to finish their 

 journey, is certainly unwarranted. 



Whatever results the new school may reach, it is 

 tolerably certain that they will eliminate from 

 the books that monster of imagination the ' economic 

 man,' and that other chimaera bombans in vacuo, 

 the hypothetical 1 consumer,' who does nothing iu 

 this world but eat. 



When they shall have rebuilt the science on their 

 new foundation, it will be soon enough to demand 

 from them an account of their views on such ques- 

 tions as Professor Newcomb propounds. 



Wm. A. Ingham. 



333 S. 16th St., Philadelphia, June 18. 



Distribution of colors in the animal kingdom. 



In the notice of Camerano's ' Distribution of colors 

 in the animal kingdom ' (Science, vii. p. 557) I notice 

 the astonishing statement that green ' never occurs 

 among mollusks.' On the contrary, it is one of the 

 most common colors of mollusks, especially among 

 fresh-water species. Examples will occur to the 

 most superficial observer in the genera Anodonta, 

 Unio, Campeloma, Anculotus, etc. Among land- 

 shells the arboreal helices of tropical countries are 

 noted for their magnificent greens. Among marine 

 shells, it is notable in many species of Mytilus, Mo- 

 diola, Tellina, Prasina, etc., among pelecypods ; Neri- 

 tina, Chlorostoma, Turbo (where the calcareous oper- 

 culum, also, is often stained with green), Haminea, 

 and many other gastropods ; not to speak of the 

 nudibranchs, which frequently exhibit different 

 shades of green. The rarest color among mollusks 

 is pure blue (as distinguished from the rather com- 

 mon bluish violet), but even this color is found of 

 great brilliancy in some cases. The assertion ob- 

 jected to is one more bit of evidence to the general 

 neglect among biologists, otherwise well equipped, to 

 gain any general knowledge of the Mollusca, except 

 that supposed to be afforded by theoretical views 

 taken from out worn text-books. There are perhaps 

 a dozen first-class general conchologists in the world, 

 none of whom are young. The prospect now is that 

 the next generation will not have any. The reasons 

 seem to be, among others, the shocking state into 

 which amateurs and superficial students have brought 

 the nomenclature, and the fact that the scientific 

 training to be had in our best colleges leads in alto- 

 gether different directions. Wm. H. Dall. 



