60 



POPULAR SCIENCE 1TEW8. 



[April, 1888. 



C orrceponJcnte. 



Brie/ communications vpon mbjects of acitTiti/lc interest 

 will be welcomed from any quarter. The editors do not neces- 

 sarily indorse all mews and statements presented by their cor- 

 respondents. 



WHERE DID THEY COME FROM? 



I NOTICE in the February number an article by 

 J. A. M., in reference to seeing vast numbers of 

 small brown frogs covering the road and vicinity 

 after a slight shower, with the above query. It 

 might naturally be inferred that they probably fell 

 from the clouds with the shower. My observation 

 leads me to a different conclusion. In the summer 

 of 1880, after a copious shower in this vicinity, 

 my colleague Dr. S. told me he noticed, in passing 

 along after the rain, for some distance on the road 

 and over the ground, great numbers of small toads 

 or frogs, which he, as well as others, supposed had 

 fallen with the rain. Having occasion the next 

 morning to pass over the same ground, I found 

 them still there, as represented. My curiosity was 

 excited; I concluded to investigate. I found their 

 presence was confined to a limited locality for a 

 distance of about eight hundred yards or less along 

 the road. In looking about, I discovered several 

 depressions or flat hollows in an adjoining field, 

 from which there were no outlets for drainage, and 

 consequently formed shallow ponds a few inches in 

 depth, and which existed there during the spring 

 and summer, forming a favorable breeding-place 

 for toads and frogs, and where they remained 

 during the time the surrounding ground was in a 

 dry state. After the ground and grass were wetted 

 by the shower, they commenced their migrations, 

 and produced the phenomenon as above. Probably 

 J. A. M. might have solved his question by a little 

 investigation of the ground in the vicinity where 

 he found them so numerous after a shower. 



Ben.i. Frantz, M.D. 



Waynesbobough, Pknn., Feb. 21. 



A C;URIOUS ELECTRICAL PHENOMENON. 

 Editors Popular Science News: 



" There is nothing new under the sun," says 

 the wise man. But when I tell you that I was 

 shocked by a cooking-stove, I think you will 

 agree with me that Solomon's saying did not apply 

 to the case of electrical phenomena. On the after- 

 noon of ]March 5 I had occasion to be around the 

 stove, which, by the way, is heated with natural 

 gas; I was about to remove a bake-pan therefrom, 

 when suddenly — in fact, as quick as lightning — I 

 perceived that " virtue had gone out of me " in the 

 shape of electricity. In my surprise, I jerked my 

 hand away quickly. Again I tried to remove the 

 pan, and met with a like experience. My curiosity 

 having by this time overcome ray surprise, I deter- 

 mined on a further investigation, and found that, 

 no matter what part of the stove my fingers hap- 

 pened to touch, the electricity was drawn forth 

 from them in thread-like streams of blue electrical 

 fire. 



A friend was present with me, and witnessed the 

 phenomenon; and, repeating the experiments, I 

 found that no apparent effect followed when her 

 fingers were brought into contact with the range. 



H. S. (ioODWIN. 



East Liverpool, Ohio, March 5, 1888. 

 — • — 

 QUESTIONS AND ANSWERS. 



Letters of inquiry should enclose a two-cent stamp, 

 as well as the name and address of the writer, vv-liich 

 will not be published. 



Questions ref;arding the treatment of diseases can- 

 not be answered in this column. 



E. C. M., St. Paul. — Is it possible to hold the hand 

 in molten copper without injury, an often stated? 



.Answer. — Under favorable conditions this is ((uite 

 possible, as the moisture of the hand is changed into a 

 protecting layer of steam, which keeps the hot metal 

 from touching it. The hand is, as it were, in the sphe- 

 roidal state, such as may be observed in a drop of 

 water spilled on a very hot stove. It is, however, a 

 very foolish and <langerous experiment for any one to 

 try; for, if the conditions were not perfectly favorable, 

 the loss of the hand would be the inevitable result. 



D. S. M , Watertovm. — It is considered by evolu- 

 tionists that tlie brilliant colors of flowers and fruits 

 have been developed by a process of natural selection 

 The brightest-colored fruits would be most attractive 

 to birds and other animals, and thus their .seeds would 

 be eaten and widely scattered, after passing through 

 the body of the animal. 



T. B. T., Vermont. — What is the principle of action 

 of the so-called " safety-matches," which light only on 

 a specially prepared surface? 



Answer. — The^e matches are tipped with a composi- 

 tion (largely chlorate of potash) which ignites readilp 

 on being brought in contact with phosphorus. The 

 phosphorus is contained in the surface upon which 

 they are rubbed, but is an allotropic form of the ele- 

 ment, known as red or amorphous phosphorus, which 

 is chemically the same as common phosphorus, but 

 is unaltered in the air, and will only ignite at a tem- 

 perature of 4fiO° F. 



C. L. G , floston — Why does blue clothing take 

 white in photographs, and red, black ? 



Ansioer. — Blue light is accompanied by a large pro- 

 portion of actinic or chemical rays, which act on the 

 sensitive photographic lilm, and cause it to appear 

 nearly white in the picture. Red light, on the con- 

 trary, is almost entirely free from such rays, and has 

 no action on the film, producing the same effect in the 

 picture as a black surface. 



J. W. S., /oujfi. — What is the philosophy of the 

 " popping" of corn? 



Answer. — It is caused by the expansion by heat of 

 the air and moisture in the interior of the kernel. The 

 outer covering of the corn is practically air-tight, and 

 tlie force exerted by the expanding gases finally causes 

 it to burst open; while the starch, of which the grain 

 is prin<'ipally composed, is puffed up by the explosion 

 into the familiar soft, spongy mass. Probably a part of 

 the starch is converted by the heat into a gummy sub- 

 stance known as dextrine, which gives it consistency 

 an<l rtavor. 



R. K., Conn. — The substance of which wasps' nests 

 are composed is a true paper, although a very coarse 

 kind. 'The fibre is gathered by the wise little insects 

 from ohl logs, fence-rails, dead limbs, etc., and worked 

 into material suitable for nest-building. The wasps 

 were evidently the originators of the modern " wood- 

 pulp" industry. 



Observer, Marblehead. — During the recent total 

 eclipse of the moon, the light was not entirely extin- 

 guished, hut the disk was apparently of a red copper 

 color. What is the cause of this appearance? 



Ansioer. — As our correspondent doubtless knows, 

 the moon is eclipsed when the earth passes between it 

 and the sun, thus cutting off the light with which our 

 satellite is usually illuminated. A portion of the sun's 

 light, however, is refracted or bent around the earth 

 by its atmosphere, so that the moon's surface is dimly 

 illuminated. At the time of the eclipse, an observer 

 upon the moon would have seen the illuminated at- 

 mosphere of the earth encircling it like a halo. 



is especially well qualified to explain its important re- 

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The same firm also publish The Story of Creation, by. 

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 written in a clear and easily imderstood style. 



A Covrse of Lectvres in Electricity, by George Forbes, 

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 trated with numerous excellent engravings. 



Home Experiments in Science for Old and Yonnii. By 

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 A book of thisdescrijition has long been needed, and 

 Professor Sloane's attempt to furnish a list of experi- 

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Outlines of Practical Phy.iioluqy. By William Stirling, 

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This work was written to supply the wants of the 

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Practical Physics. By Professors Balfour Stewart and 



W. W. Haldaiu: Gee. Published by Macmillan & 



Co , New York. Price (iO cents. 



This work is especially designed for students in high 



schools and colleges, and largely consists of sinqde 



experiments and measurements in electricity and 



magnetism, and the explanations of the principles 



involved. Numerous praciical details are given iiin- 



cerning the best and cheapest forms of apparatus, and 



the methods of their constiucticm and management; 



rendering it a most valuable book to all teachers or 



students of the .science. 



LITERARY NOTES. 

 Modern Theories of Chemistry . By Dr. Lothar Meyer. 



'Translated by Professors Bedson and Williams. 



Published by Longmans, Green, & Co., New York. 



Price «5.50. 



When, some fifteen years ago, Professor Cooke 

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 As one of the discoverers of the periodic law, the author 



The Manual -Traiainff School: its Aims, Methods, and 

 Resnlts. By Professor C. M. Woodward, of the Man- 

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 Louis. Price .$2.00. Published by D. C. Heath & 

 Co.,' Boston. 



This book is exceedingly practical, its main object 

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Messrs. Mariani & Co , 127 Fifth Avpmie, New York, 

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> 



Pamphlets, etc., received: A Review of Profiress in 

 Artsand Mann factnres during MSr, by William H. Wahl, 

 Ph.D ; The fail of the Earth (25 cents), by William 

 Danmar, Brooklyn, N Y.; ': he Construction <if Maps in 

 Relief, by Messrs. John and Edward Harden; The 

 Nati'onal'Sin of Lilerarii Piracy (price 5 cents), Charles 

 Scribner's Sons, New York; Ihnc to Grow Straicberries, 

 by the editor of tlie London, Ilorticidtural Times and 

 others; and The Relation of Science to Agriculture, by 

 N. T. Lupton of Alabama. 



From lack of space, the notice of sex'eral other 

 volumes received must he deferred till next month. 



