278 



SCIENCE. 



[Vol. I., No. 10. 



very different from that of Rio de Janeiro (one of the 

 nearest coast-towns where observations have heen 

 made) and that of Sahara (some 250 miles to the east- 

 ward, near the western margin of the mountainous 

 area of eastern Brazil), and is somewhat greater than 

 that of Sao Paulo (situated 35 miles from the sea, be- 

 hind the first ridge of the maritime range). 



Note. — In reducing to inches, hundredths have heen disre- 

 garded. 



Oeville a. Derby. 



LETTERS TO THE EDITOR. 



I requested to be as brief as possible. The 

 writer^s name is in all cases required as proof of good faith.] 



Pairing of the first-born. 



In Science of March 16, p. 167, Charles S. Minot 

 estimates the chance of the iirst-born male pairing 

 with the first-born female, where there are ten birds 

 of each sex to pair, as one to one hundred. It Is easy 

 to see that the first-born male must pair with one of 

 the ten females : he is, therefore, as likely to pair 

 with the first-born female as with any other one; and 

 hence the chance that the first-born male will pair 

 with the first-born female is as one to ten, instead of 

 as one to one hundred. J. E. Hendricks. 



Des Moines, March 27, 1883. 



Thermal belts of North Carolina. 



The abstract of Prof. J. W. ChicUering's paper on 

 the above topic (Science, p. 147) has suggested to 

 me the propriety of putting on record the results of 

 observations made by me many years ago, on the 

 ' frostless zones ' of the flanks of the mountain spurs 

 adjacent to the valleys in the Blue Ridge. My obser- 

 vations were made at Flat Rock, near Hendersonville, 

 Henderson County, N.C., — a well-watered, fertile, 

 mountain-plateau-like valley, which is about 2,200 

 feet above the sea-level. 



My own observations, and the information elicited 

 from residents, seem to indicate the following facts, 

 which, if verified in other places, may have a bearing 

 on the physical causes which give origin to the ' frost- 

 less zones'; viz., the zones in question are not ex- 

 empt from frost during the whole of the cold season : 

 in fact, during the winter, tlie ground in these belts 

 is frequently frozen to a considerable depth; but 

 during the spring months they are conspicuously and 

 uniformly frostless. They coincide with the noc- 

 turnal and morning 'fog-belts' of the spring months. 

 The uniform presence of these white, circumscribed 

 belts of fog on the flanks of the mountain spurs, 

 during the early morning hours, imparts a striking 



feature to the scenery of these valleys. When illu- 

 minated by the hright morning sun, they appear like 

 girdles of cotton-wool of moderate width, encircling 

 the peaks at the height of 200 or 300 feet above the 

 adjacent valleys; and their cumulus-like whiteness, 

 contrasted with the verdure above and below them, 

 is no less striking than it is beautiful. 



The latter circumstance seems to furnish an expla- 

 nation of the physical cause of the so-called ' thermal 

 belt ; ' for the constant fogs at night and in the morn- 

 ing not only prevent refrigeration by obstructing ter- 

 restrial radiation, but, during tlie condensation of 

 vapor in the process of fog-formation, there must be 

 developed an enormous amount of heat just at this 

 zone. Why this condensation of aqueous vapor 

 should be so persistently restricted to a belt of only 

 a few hundred feet in vertical thickness, is a question 

 much more difficult to answer. 



The observations of intelligent residents of the 

 mountain valleys, in the southern divisions of the Ap- 

 palachian chain will doubtless verify or disprove 

 the general coincidence of the ' frostless zone ' with 

 the ' fog-belt ; ' and this is the point which some 

 of the readers of Science may be able to settle. 



John LeConte. 

 Berkeley, Cal., March 27, 1883. 



Plight of the flying-fish. 



A note in Science of March 23, concerning tlie 

 flight of the flying-fisli, leads me to offer the results 

 of my own observations. During a passage through 

 the Indian Ocean in 1880, I had so numerous and 

 excellent opportunities for observing the movements 

 of flying-fish in all kinds of weather, that I deter- 

 mined to discover, if possible, whether or not the 

 wings were of material aid in flight, beyond a mere 

 buoyant action. In many cases the fish would con- 

 tinue its flight for a surprisingly long period, some- 

 times in the face of the wind. Again, the direction 

 of flight would be changed in such a way as to render 

 it improbable that the wind was the cause. When an 

 object is passing over a rapidly changing surface, it 

 is very easy to imagine it to rise or fall in unison with 

 the latter; but so frequently did I notice a fish clear 

 advancing waves, that I finally was forced to believe 

 them to have the power of controlling their flight. I 

 frequently called upon other passengers to confirm 

 my own observations, with which their testimony was 

 in general harmony. I may say, therefore, that I 

 finally reached the same conclusions as those pre- 

 sented by Mr. Kneeland. D. P. Pbnhallow. 



Mountainville, N.Y., March 29, 1883. 



THE NATURAL HISTORY OF OHIO. 



Report of the c/eolor/ical siiroey of Ohio. Vol. iv. 

 Zooloc/y and botany. Part i. ZoiHogy. Pub- 

 lished by authority of the legislature of Ohio. 

 Cohunbus, State, 1882. « -|- 1020 p. 8°. 



This long-looked-for volume has appeared, 

 and, notwithstanding its size, includes only 

 the vertebrates of the state. Dr. Newbeny, the 

 head of the surve}', holds out some hope of a 

 future volume on the invertebrates and on the 

 botany of the state ; but the ditticult3' experi- 

 enced in securing further appropriations for 

 the publication of the fossil remains leaves 

 their appearance rather doubtfuk 



The part devoted to the mammals (a hun- 



