484 



SCIENCE. 



[Voi,. VII., No. 173 



Errata. 



In these days of co-operative enterprises there is 

 a chance of success for many a useful scheme that 

 m other times would be Utopian ; and so the writer 

 would like to suggest the usefulness of a separate 

 systematic publication devoted to errata, to appear 

 at intervals as materials accumulated for it. In it 

 any student of an important book might hope to 

 find collected all the important errors that critics 

 and other readers had discovered. These errors 

 might be disturbing misprints, slips in dates or the 

 spelling of a name, mistakes in formulae or mathe- 

 matical tables, etc., or possibly might extend to very 

 brief criticisms on a book for the omission of very 

 important facts bearing on the argument, or the use 

 of unreliable authorities. Just how far it would be 

 safe or desirable to go into such criticism, must, of 

 course, be left to the judgment of the editor. 



If such a plan commends itself to those who use 

 books, and therefore want them to be correct, it 

 ought not to be difficult to put it into operation 

 through the co-operative work of public spirited 

 publishers, and of the librarians, who have already 

 done so much for book -users, that in our gratitude 

 to them we have the proverbial ' lively sense of 

 favors to come.' 



If the publication of such a list as this were started, 

 either as an independent venture or as a supplement 

 to the Publishers' weekly or the Library journal, we 

 cannot doubt that many readers all over the country 

 would gladly furnish contributions to it ; and such 

 scattered corrections as one finds in newspaper re- 

 views of a book would be collected in a way to be 

 useful to all who use the book in question. 



C. K. Wead. 



Popular astronomy. 



Permit me to make a few remarks on the review 

 of my 1 Story of the heavens,' which appeared in 

 your issue of April 23. 



You first charge me with appropriating a figure on 

 p. 78 of Professor Newcomb's 'Popular astronomy,' 

 and you assert that the text relating thereto has been 

 borrowed from him. I refer to my ' London science 

 class-book of astronomy,' articles 60 to 03, where 

 essentially the same figures and reasoning are used. 

 This was published in 1877 ; Newcomb's, in 1878. 

 No doubt I had read Newcomb afterwards, and pos- 

 sibly improved on the original illustration by so do- 

 ing. Probably the same idea has occurred to many 

 others besides Newcomb and myself. 



You also charge me with taking illustrations with- 

 out acknowledgment, yet ou*t of one hundred and 

 six figures you only cite one (p. 228) to support the 

 charge. The extent of my offence is just this : iu 

 the original manuscript of my book I had referred 

 to Newcomb, but I struck out the reference from the 

 proof in the belief that he would not care to be cited 

 for so trivial a matter. 



The two passages from Professor Young's ' Sun ' 

 have been unconsciously adopted by me by a care- 

 lessness which I sincerely regret. They were copied 

 some years ago for use in my lectures ; they passed 

 into my manuscripts, and I lost sight of their origin, 

 and treated them as my own language, which, until 

 my attention was called to the matter by your re- 

 view, I believed them to be. 



While I am glad to have my errors pointed out, 

 and to make what reparation may be possible, I must 

 indignantly protest against the tone of your com- 



ments. You have fastened the worst construction 

 on these blots, and accuse me of pillage. The simplest 

 principles of justice should have required you to hear 

 my explanation before you make so serious an allega- 

 tion. You have even spoken of it as wholesale pil- 

 lage, with what justice Heave your readers to decide. 

 I have added the lines in the passages impugned in 

 your review, as well as in the kindred review in the 

 Nation ; I have also added the equivalent of the 

 illustration on p. 228 ; and I find the whole amounts 

 to two pages and'a half, while the entire volume con- 

 tains five hundred and fifty-one. Robert S. Ball. 

 Dublin. May 12. 



[We are glad to publish Professor Ball's reply to 

 the critics of his book, and hope that he will feel 

 fully vindicated by the letters from Professors New- 

 comb and Young in Science of April 30. — Ed.] 



Barometer exposure. 



You gave a place to my letter showing how ther- 

 mometers were affected by the place of exposure : 

 will you now allow me to point out how the barometer 

 also seems to be thus affected ? 



At the Blue Hill observatory, during high winds,, 

 the barograph shows sudden small oscillations, which, 

 on watching, have been found to be coincident with 

 changes in the wind's velocity. When the wind 

 rushes by with increased velocity, the barograph 

 sinks ; and when the wind subsides somewhat, the 

 barograph rises again slightly. About noon on 

 March 16 the wind's velocity rapidly rose from five 

 to thirty five miles, and the barometer suddenly fell 

 five-hundredths of an inch. During a sudden gust 

 attending a shower last summer, the barometer fell 

 a tenth of an inch, and immediately rose again as 

 the gust ended. These facts all suggest that the 

 wind, in blowing by at right angles to the cracks and 

 crevices in the building, produces a mechanical 

 effect, which tends to draw the air out of the build- 

 ing, and decrease the pressure inside. In confirma- 

 tion of this conclusion, whenever, during high winds, 

 the hatchway in the top of the tower is opened, it 

 gives a larger aperture for the wind to act on, and 

 the pressure on the inside immediately falls. It fell 

 as much as a tenth of an inch during a seventy-mile 

 wind in February. This seems to point to the con- 

 clusion that during high winds the barometer reads 

 too low. 



In Loomis's fifteenth paper in the American jour- 

 nal of arts and sciences, he discusses the reduction to 

 sea-level of the barometer-readings on Mount Wash- 

 ington, and finds a number of cases in which the 

 barometer readings, when reduced to sea-level by 

 the formulas usually in use, are three-tenths of an» 

 inch or more lower than would seem to be the true 

 readings as determined from the neighboring stations 

 of Burlington and Portland. These cases all oc- 

 curred when the wind was very high on Mount 

 Washington, the average being sixty-six miles per 

 hour, and some cases showing as much as a hundred 

 miles. In his remarks, Loomis says that these " great 

 anomalies are confined to the colder months of the 

 year, and seldom occur except during the progress 

 of violent storms." 



This suggests that at Mount Washington, as at 

 Blue Hill, and probably elsewhere, the wind, in blow- 

 ing by the building with great velocities, produces a 

 partial vacuum inside. H. Helm Clayton. 



Blue Hill observatory, May 18. 



