296 



SCIENCE. 



[Vol. IX., No. 216 



expense of manufacttire and material is much less, it 

 •would seem as though it should be adopted, and at- 

 tention turned to the weight, friction, shape of sur- 

 face, etc. 



Complaint is made of short, light vanes, that they 

 often make a complete revolution in high winds. 

 This could be obviated by increasing the weight, but 

 this would not be as satisfactory as increasing the 

 length. It is very evident that the same vane will 

 not answer for both light and heavy winds. It 

 would seem as though a long flat vane would do for 

 the higher winds ; and the lighter winds may be de- 

 termined by the motion of smoke or a light banner, 

 always being careful to keep the line of sight at right 

 angles to the wind. This question is an eminently 

 practical one. Experiments are much needed to de- 

 termine the most satisfactory size of surface, length 

 and weight of vane, for winds of different velocities, 

 to satisfy the conditions first laid down. 



Since writing the above, it has been suggested to 

 me that the double vane can be so readily braced, it 

 can be made out of very light material, and hence may 

 be much lighter than the flat vane. The fallacy here 

 consists in the implication that a single vane needs 

 any bracing at all. Since there is no strain upon a 

 flat vane, as it always turns immediately into the air- 

 current, it need not be very stiff ; but it is far other- 

 wise with the double vane. Here the spreading of 

 the tails at once brings a tendency to collapse, to 

 each tail, which increases with the wind-velocity, 

 and is never absent, being greatest when the vane is 

 in the air-current. Each tail, then, must be far 

 stiffer than the single tail, which has no strain at any 

 time. But this is not all : the material used in the 

 bracing will add much to the weight, especially with 

 the greater angles of the tails. For example : take 

 the most sensitive vane, where 2i = 90" and e = 45°. 

 If the tails are 4 feet long, the spread at the tips will 

 be 5.6 feet. A width of half a foot would give a 

 strain of 30 pounds, with a wind-velocity of 40 miles 

 per hour, and the tails must be very stiff. In addi- 

 tion, if the web bracing is as stiff as the tails, the 

 total weight would be more than four times that of a 

 single vane with double the surface and better fitted 

 for service. H. Allen. 



Philadelphia, March 15. 



On certain electrical phenomena. 



There are a few mystics in science (I am not one 

 of them), but I fail, even upon a second readinjj, to 

 discover that shroud of mystery enveloping my letter 

 ' On certain electrical phenomena' {Science, No. 211), 

 which seems to have impressed ray critic, ' T. C. M.,' 

 in a subsequent issue (No. 213). 



My letter was copied into a number of the daily 

 papers in the pastern and western cities, and I have 

 letters from people who are strangers to me, in re- 

 gard to it ; but thus far, excepting • T. C. M. ,' no 

 one seems to think it * mysterious.' I am sure I did 

 not when I wrote the account. 



Your correspondent furoher advises me that I 

 should 'possibly eliminate a few of the facts' in 

 making such investigations, to which I can only re- 

 ply that I am not in the habit of eliminating any of 

 the facts in the premises of any scientific investiga- 

 tion I may be engaged in, whatsoever may be its 

 character. Usually I gather and use all such facts 

 as I can lay my hands on. 



As the point is an important one, I would also like 



to say to Professor Mendenhall that he evidently 

 misquotes me in the next paragraph of his letter,, 

 wherein he says that " Dr. Shufeldt states that he had 

 never observed such exhibitions in Washington." I 

 made no such statement, but did remark that "I had 

 never observed (there) such exhibitions so far as my 

 own person was concerned, and they only gradually 

 developed at this place " (Port Wingate, N. Mex.). 

 The cases cited for that city by him are very inter- 

 esting. 



I repeat, that in my case the " electrical discharge 

 was considerably greater from the tip of the index- 

 finger than from any of the others of the hand, and 

 gradually diminished in regular order as we pro- 

 ceeded to the little finger ; " and this after careful 

 experimentation. I nowhere even imply that this 

 will be found to be universally the case. 



Further, your correspondent seems to hold the 

 opinion that every one exhibits such electrical phe- 

 nomena in the same degree, when submitted to simi- 

 lar conditions to excite it. In this I thoroughly dis- 

 agree with him ; for further experimentation here, 

 goes to show that phenomena similar to those I de- 

 scribed in my letter to Science are exhibited in vary- 

 ing degree by my three children, whereas on the other 

 hand, in the case of the mulatto child I referred to, 

 it has thus far, after numerous trials, been impossible 

 to excite them in her. 



And I must believe, that, when Professor Menden- 

 hall comes to make more extended inquiry among a 

 greater number of people, he will discover that there 

 are many of them who have absolutely never heard 

 of such things, to say nothing of having observed 

 them in the case of their own persons. Common it 

 is, no doubt ; and, ah, me ! how wise we would all 

 be if we were but only thoroughly informed upon all 

 common phenomena ! R. W. Shufeldt. 



Fort Wingate, N. Max., March 10. 



Comparative taxation. 



It is true, as Mr. Atkinson says, that it is easier to 

 criticise than to construct, and Mr. Atkinson deserves 

 credit for his undertaking. Yet criticism of what 

 has already been done may be of value in clearing 

 the way for more perfect work in the future, and I 

 therefore venture to offer a further criticism of some 

 of the views expressed in Mr. Atkinson's letter of 

 March 4. 



Mr. Atkinson gives, as a reason for considering 

 national taxation separately, the fact that in Europe 

 so large a portion of the national revenue is expended 

 for ' destructive purposes,' by which I suppose is 

 meant war purposes. The difference between Europe 

 and this country is not so great as most people prob- 

 ably believe. If we consider the army and navy and 

 pensions, which are a war expenditure, we find that 

 in 1885-86 the German empire expended for the 

 above purposes $110,500,784, and the United States 

 $111,636,903. A comparison of the relation of these 

 expenditures to total expenditures in the two coun- 

 tries is rendered difiicult by the different character 

 of the governments ; but considering only the ordi- 

 nary governmental expenditures, that is, omitting 

 the consideration of railways, mines, etc., we find 

 that in the United States war expenditures amount to 

 39 per cent of the whole ; in the German empire, ex- 

 clusive of the individual states, to 77 per cent ; and 

 iu Prussia and the empire taken together, to 28 per 

 cent. 



