June 23, 1893.] 



SCIENCE. 



347 



ated clouds float into the wind in opposition to all known physi- 

 cal laws ? 



I cannot help but think that had a meteorologist been on the 

 spot, he would have been able to throw light on the subject of 

 cloud formation and precipitation. Alt ah A. Eaton. 



Rlverdale, Cal., May 20. 



Birds that Sing in the Night. 



I WAS somewhat surprised that the writers under the above 

 caption in the Dec. 2 and 16 Nos. of Science omitted some of the 

 most familiar night-singers of the Atlantic seaboard of the latitude 

 of New England. While never having heard some of those men- 

 tioned, I have often heard the field-sparrow, Shizella pusilla, 

 break forth into rapturous song by night, especially if the moon 

 be shining, at the nesting period. 



Another of the most common night-singers is that songster of 

 songsters, the prince of the thrushes, the Wilson's thiush, or 

 " Marten," Turdus fuscescens. During late May, June, and early 

 July he prolongs his vespers till nine or ten o'clock, and often 

 breaks forth at intervals throughout the rest of the night. 



Another songster is the cuckoo, whether the yellow or blue- 

 billed, I know not. He generally sings in the low ground, and is 

 popularly supposed to foretell rain. "Oft in the stilly night," 

 while the moon was playing hide and seek with the clouds, and a 

 thin mist was creeping slowly over the landscape, have I heard 

 the "rain-bird's" voice come weirdly from the swamps. At first 

 low and indistinct, perhaps owing to the inequalities of the at- 

 mosphere, a few steps may sufiice to place one so it is heard with 

 startling distinctness. At such times the sweetness of his voice 

 is enhanced, and, as the clear, liquid notes swell on the stillness, 

 we forget to quote Shakespeare : " The nightengale if she should 

 sing by day, would he thought no better a musician than the 

 wren," but rather burst into the rapturous quotation of a later 

 poet: — 



' ' cuckoo I shall I call the bird 

 Or but a wandering voice I ' ' 

 Then we forget the songster's ill-repute as an egg-thief, forget his 

 benefits to the agriculturist, and love to feel the author of this 

 melody is of supramundane origin, and not of earth, earthy. If 

 a few birds' eggs mixed with a diet of tent caterpillars will 

 make such a voice, let him have them, by all means. I heartily 

 believe the bluejay is author of most of the mischief laid to his 

 dooB,«as I have seen him take both eggs and young of the smaller 

 birds. 



The horned lark, Otocorie a rubed, is the most common night- 

 singer in California, at least the valley. Alvah A. Eaton. 



Rlverdale, California. 



Books for Children. 



Me. Frank Waldo, in SewJice for June 16, asks for lists of books 

 that will enable children of ten to call by name the natural ob- 

 jects they meet in their rambles. 



He says that those books which he has seen do not give the 

 "necessary details." Therein lies the difficulty with children of 

 ten years of age. As soon as the necessary details are given so 

 many scientific words have of necessity been used that the results 

 are beyond the comprehension of the clientage to which he pro- 

 poses to cater. Those whom he wishes to reach, need just what 

 he himself states at the end of his letter he was so fortunate as to 

 have, viz . a personal guide and instructor. 



The best book, for children, about flowers, with which I am ac- 

 quainted, is Gray's, " How Plants Grow." Bright children of 12, 

 if properly instructed, could use it in the woods and fields and 

 find out, without the presence of a teacher at the time, the name 

 of any of the larger and more interesting of the flowers, exclud- 

 ing, of course, the golden rods, daisies and other composite. 



In the correspondent's state. New Jersey, there are several hun- 

 dred species of birds, and many of them have nests and eggs so 

 nearly alike, that by them even oologists cannot tell the species 

 with certainty. Most birds give several different notes, some an 

 extensive range; nearly all sing differently at different times of 



the year. The bird book asked for — one that will enable a per- 

 son of ten or any other age to name "free birds" without a 

 teacher — is an impossibility. 



The best book on birds, is probably Coues's "Key to North 

 American Birds," but it could not be used by children under 15. 



French's " Butterflies of the Eastern United States," is probably 

 rudimentary enough for children of 12-14, provided a little pre- 

 liminary work were done by an older person who understands the 

 vocabulary used by the author. My own " Trees of the Northern 

 United States " deals only with the leaves, bark, and occasionally 

 the fruit, and contains as few scientific words as possible, and 

 those are all defined with added illustrations whenever at all 

 necessary. This fact, and its containing an accurate picture of 

 the leaf of each species, ought to enable even those of ten to use 

 the book. Binney's " Land and Fresh Water Shells of North 

 America" contains illustrations of all the species, and, as far as 

 these will enable one to name shells, ought to be all right for 

 children. I attempted in my " Mollusks of the Atlantic Coast" 

 to make an easy book to be used by children ot 14 or more in 

 naming the shells of the shore. 



The beetles are too numerous in species for any book, large or 

 small, expensive or otherwise, to enable children or even grown 

 people to name all or even a majority of them. The moths are 

 also very numerous in species and so far no one book, cheap or 

 high priced, names them all. Austin C. Apgar. 



Trenton, N. J. 



Teaching of Biology. 



The recent discussion in the pages of Science as to the methods 

 of teaching biology now in vogue in this country, has brought 

 out much that is of interest to all who seek to present that sub- 

 ject in a fair and unbiased manner to their students. Ignoring 

 the controversial phase, which too many of the letters have 

 shown, is there not, after all, the question yet remaining — How 

 shall biology be taught? 



Circumstances are alike at no two colleges in this country ; 

 differences of courses, students, surroundings and many other 

 factors make it necessary that each teacher should solve the 

 problem for himself. But in a large number of institutions the 

 plan of study is such that unless a student elects to specialize in 

 biological lines he will receive but one, or at most two, terms of 

 training in natural history. 



In such a case what is the best plan to adopt? A course in 

 botany will give the student a slight acquaintance with some of 

 the flowering plants only if the course be the one usually given 

 in such cases. On the other hand, a course in zoology would 

 leave the student with no knowledge of plants and but little of 

 animals. He will receive no farther work in either line during 

 his course. What will be the best for him in his life after leaving 

 college? 



After much consideration, the writer has sought to find a way 

 between the two horns of the above dilemma by seeking to pre- 

 sent fundamental principles, illustrating and demonstrating them 

 by examples taken from either the animal or vegetable kingdom, 

 as might be most advantageous. In this work the form itself 

 has received far less stress than the principle which it illustrated, 

 and the bearing it might have on the question whether the course 

 was more botanical than zoological was not for a moment con- 

 sidered. 



It was found convenient to begin by assuming that, in a de- 

 gree, animals and plants are machines for the transformation 

 and utilization of energy; adding to this, during the course, a 

 consideration of the problems which must be successfully met to 

 ensure existence and comparative study of the various ways in 

 which these problems are solved. 



The result of this course has been to encourage me to continue 

 along these lines, reserving for psychology, which follows, the 

 task of checking any tendency to regard living things as ma- 

 chines only. Looking over the ground covered, I find that nearly 

 two-thirds of the examples chosen to illustrate the various prin- 

 ciples were from the vegetable kingdom. Surely, whatever else 

 it may be. this is not a course in zoology masquerading under 



