characteristic of continental sediments, the local breaks not representing a loss of geologic time of any marked historical value." The plants certainly do not uphold this contention, but they do indicate a very considerable hiatus between the top of the acknowledged marine Cretaceous section and the inauguration of the Lance. The Laramie is not known within this area, but can it be doubted that it was the interval during which in other areas beds of Laramie age were laid down and subsequently removed in whole or in part? That there was an important interval of some kind is also shown by the fact that it was sufficiently long for over 60 per cent. of the marine Cannonball fauna to be derived through modification of the typical Fox Hills fauna. F. H. KNOWLTON PROOF OF NON-DISJUNCTION FOR THE PHILA MELANOGASTER DURING the spring and summer of 1920 I secured genetic evidence that strains of D. melanogaster haploid for the fourth chromosome had been produced by non-disjunction, and in November cytological verification was obtained. The fact that non-disjunction of the fourth chromosome is known to occur is perhaps the strongest reason for believeing that the aberrations observed by Dr. Little1 may be the consequences of non-disjunction. The direct evidence presented by Dr. Little by no means proves such to be the case, which is unfortunate, considering the ample means in D. melanogaster for checking up this hypothesis by means of other fourth-chromosome mutants (bent, shaven) and especially by direct cytological examination. Probably Dr. Little will include such evidence in his forthcoming detailed report. For the present, his published evidence is in better conformity with the assumption of a less extreme eyeless allelomorph, or of a dominant fourth-chromosome "minus" modifier. On the non-disjunctional view selective reduction of the three fourth chromosomes present is required, but there is no obvious reason why E and e 1 SCIENCE, 53: 167. should always go to assumed. A simple on the weak-allelomo weak allelomorph and Ee-e is simply seg compound. Linkage on the modifier view, f nant minus modifier some, and Ee-e is s as can be judged from all the observed ratios either of these views. proved by direct and case is actually one has he proved it negat recognized alternative equally valid and ever the facts of the case a SURVEYING THE article on Su December 17, 1920, is of the Coast and Ged lines of aerial photog does not go into the re the reasons for maki ment: These experiments pro photographs from the ai ment, are of little prac grapher. This statement has b T. Lee, of the U. S SCIENCE, February 18, Rendus Tome 169, Oc mention is made of where successful phot of the bottom at a meters. During the experim results of which wer known to me, occasi graphs of the bottom of 35 feet and less. N photograph at greater clusion regarding the " photographs was arri garding their use for hydrographic purposes were considered. Obviously, a comparison was made with the present-day methods of hydrographic surveying. It may be argued that aerial photography is more rapid, because a photograph of more than one square mile is made in a fraction of a second, and a strip 70 miles long and over a mile wide can be photographed in an hour. There are several problems to be overcome by both the aviator and the hydrographer before this can be done. Weather conditions along the sea coast are not as suitable for aerial photography as might be expected. Let us see how the photographs as made by the French would apply to our waters. These photographs were made under the following conditions: Focal plane horizontal; altitude, 2,600 meters; at time of low water; the sun high above the horizon; calm sea. Along the coast of the United States, a calm day is generally hazy, so much so that it is impossible to make photographs from an altitude of even 4,000 feet without special treatment of plates or films. We are aware of recent experiments regarding the penetration of haze, but at the time the Key West experiments were made, little was known of this new process. Further developments may make it possible to penetrate haze at altitudes of 2,600 meters. But disregarding haze, those days that are calm and cloudless are infrequent. It is difficult to obtain data regarding meteorological conditions as affecting aerial photography along the coast, but from available data, it is ventured that about one day a month would fulfill conditions as called for by the French, and that is believed to be an optimistic esti mate. Regarding control for the photographs, very few places along our coast are as ideally fitted for control of aerial protographs as the area chosen near Brest. This locality is dotted with numerous small islets, and ample control could be obtained for each photograph. At Key West, it was necessary to use boats as control points, so that the speed at which an area was covered was limited to the speed of the vessels. There are a few places along our coast where enough land stations pear for control, but these areas are in bays or rivers where water is enough for good photographic work or rafts may be used as control p the cost and labor of handling the be excessive. A raft about 10 feet in would be needed in order to be leg 1:10,000 scale photograph. The p handling a large number of these signals would require a good sized crew. The uncertainty of results is anoth The French have solved some of the by using the stereoscope, so that t sion, brought about by vari-colored uniform depth, is partly eliminate shoals will show clearly, while other do not appear in the photograph, pro to a difference in color or light photographs will not record all shoa by the aviator. It is often necess: over the same area repeatedly in or tain good results. Unless ideal conditions prevail, t an aerial survey with present-day will far exceed that of a wire dr and will not give as certain result lieve that aerial photo-hydrography use in a few limited locations, and possibilities of future development, present date, revision work by phot land holds forth greater promise, in which more certain results can b It may be of interest to quote from a letter dated January 10, Le Directeur du Service Hydrogr dressed to the Director of the Coa detic Survey, in which the follo ment is made regarding aerial 1 along the coast of Syria in 1920. Les circonstances n'ont d'ailleurs Į l'employer systematiquement. (The do not, however, permit of its system: A careful analysis of the conclu in the article "Surveying from the cially of the qualifying words "us day equipment," and "little prac will probably derive the result that the statement is not as hastily worded as it was first thought to be. E. LESTER JONES SCIENTIFIC BOOKS Physics of the Air. By W. J. HUMPHREYS, Professor Humphreys states in his introduction that "it is obvious that an orderly assemblage of all those facts and theories that together might be called the Physics of the Air, would be exceedingly helpful to the student of atmospherics." Of this there can be no doubt, and the author has rendered a great service by thus bringing together and making easily available material that otherwise would have remained scattered through technical magazines, official publications like the Monthly Weather Review and journals of organizations like the Royal Meteorological Society. The volume had its inception in a series of lectures delivered by Dr. Humphreys at the San Diego Aviation School in 1914. These lectures revised and printed from month to month in the Journal of the Franklin Institute, 1917, 1918, 1919 and 1920, are now consolidated in one volume. As late as 1917 our military authorities failed to appreciate the importance of a knowledge of aerography, that is, the structure of the atmosphere. In June of that year a high officer of the Signal Corps, at that time entrusted with aviation, wrote: It has frequently happened in the past that men who might otherwise have made good pilots became so alarmed in advance over the subject of "holes in the air" and so impressed with the terrible dangers of aerial navigation, that they never succeeded in gaining the necessary confidence to become good pilots, etc. This was given as a valid reason for refusing to utilize recent advances in meteorology! And again: So little time is avail sity for extreme haste service overseas that t give more than the elen or two lectures. These views are re show in some measu inertia which had many promising lives need of the fullest manifest; and before raphy had come into and navy schools of Professor Humphr into four main parts; dynamics; atmospheri atmospheric optics; control. The author of access to the Weat critical readings by 1 more, the text appea publication. The wor typographical errors. а There are a few s 49 the symbol for t thermal region T mig been placed in front least in some way s present. Again, it wo of saying that the radiator, in this case absolute, the author mon form 259° A., necessary, in degrees text-book to avoid co sistent notation. The is not good form to sp ture as 259° C. absol the next page give a same value in degre -14° C. One may from such loose pract On pages 75 Occurs. so great the necesaring aviators for no opportunity to meteorology in one here, simply to mount of official vercome. After sacrificed, the e possible was - ended aerog- n. s his treatise s and thermo - and auroras; s of climatic eat advantage Library, and es. Further before final ly free from . On page of the isoantage have ical, or at re than at if instead f a black as 259° C. more com hought it rable in a sing conIs that it temperae and on ssing the that is, ta slip ough it ated: he earth ! arse the erature cale is 260°. There is a scale which might have been advantageously used here, namely the Kelvin-Kilograde scale. True, few are as yet familiar with it; but the colors should always be in advance of the line, not abreast nor yet behind. In an up-to-date scientific book we have the right to expect leadership rather than tolerance. The airman has got to forget the unscientific, arbitrary scales of his fathers; and stop using inches, minus signs, etc. His range of temperature is from summer day surface values to winter sub-polar readings near the stratosphere; and old-fashioned methods are inadequate. Pressures are generally given in this book in millimeters of mercury with occasional lapses into inches. In a treatise dated 1920, one might look for pressure values throughout in units of force, that is, dynes or kilodynes per square centimeter. In the chapter on "Atmospheric Circulation which is well put, and more clearly explains the mechanics of deflection than most other text-books, it is demonstrated that in the case of a wind with a velocity of 22 meters per second, there will be a modification of velocity, depending upon whether the wind is blowing east or west; that is, a given mass weighs less going east than going west. A note might have been added giving results of recent gravity determinations at sea on fastmoving (22-knot) destroyers (25-mile-per-hour vessels); in which it was definitely ascertained that the barometric pressure changed 0.1 kilobar (0.075 mm.) when the course was reversed. Going east with the earth the centripetal force is greater than when steaming west. All this is of importance in connection with fast-moving airships.1 The discussion of change of velocity with latitude, deflective effect of the earth's rotation, relative values of centrifugal and rotational components, and gradient winds, is thorough and well expressed. Of course, the explanation of friction acting as the effective damping factor against high rotational winds 1 See SCIENCE, February 6, 1920; also January 9, 1920. is no longer tenable; and there is no emphasis laid on the fact that the tive values are hypothetical, not rea mobile air is involved. Chapter XI., on "Winds A Aviation," explains the so-called the air," "bumps," "dunts," etc. T a mathematical symbol in the whol The different phenomena are exp straightforward, simple language. there is much yet to be learned in with favorable and adverse condit we await some Maury who will do logs of airships what the old Comm with the logs of the clippers of his Chapter XIV. contains many pl of cloud forms, but neither here r first chapter where many instru given, is mention made of a nephoso credit for cloud work done at Blue servatory is not given; nor is men of Professor Bigelow's Internation Report. Chapter XV., on "The Thunders 105 pages, and yet is not included in dealing with Atmospheric Electr Auroras, which has only 18 pages. Part III., on "Atmospheric Optics pages and is based largely on the w Pernter-Exner "Meteorologische O Mascart's "Traité d'Optique." Part IV., 74 pages, deals with climatic control, that is, in the auth a discussion of the physics of climat of its geographic distribution. factors considered are latitude, bri the moon and planets, solar const distance, obliquity of ecliptic, perihel extent and composition of the a vulcanism, sun spots, land elevation water distribution, atmospheric c ocean circulation, and surface cove Elaborate tables of gradient wind are given in the appendix. We no minor typographical errors. On latitude 10°, the change of directio not 261, and the heading needs re page 162, m.m. should be mm.; on figure 31 should be 32; and on page 57, the lengend should give the elevation of the REPORT OF THE COMMITTEE ON NOMENCLATURE OF THE BOTANICAL SOCIETY Ar the Baltimore meeting of the Botanical Society of America (1918), the Committee on Generic Types presented a set of rules for fixing the types of genera. The report was published in SCIENCE (49: 333-336. 1919). At the same meeting the committee was enlarged to nine members and made a standing committee on botanical nomenclature, with authority to prepare a code of nomenclature. The standing committee consists of LeRoy Abrams, N. L. Britton, E. A. Burtt, A. W. Evans, J. M. Greenman, A. S. Hitchcock, M. A. Howe, C. L. Shear and Witmer Stone. The actual work of elaborating a code was done chiefly by a subcommittee consisting of J. C. Arthur, J. H. Barnhart, R. S. Breed, N. L. Britton, O. F. Cook, F. V. Coville, A. W. Evans, B. Fink, A. S. Hitchcock, M. A. Howe, F. H. Knowlton, P. L. Ricker, C. L. Shear and H. C. Skeels. The following code was presented by the committee: A TYPE-BASIS CODE OF BOTANICAL NOMENCLATURE PRINCIPLES 1. The primary object of formal nomenclature in systematic biology is to stability, uniformity, and convenience in the designation of plants and animals. 2. Botanical nomenclature is treated as beginning with the general application of binomial names to plants (Linnæus' "Species Plantarum," 1753). 3. Priority of publication is a fundamental principle of botanical nomenclature. Two groups of the same category can not bear the same name. Note a. This principle applies primarily to genera and species. Note b.-Previous use of a name in zoology does not preclude its use in botany; but the proposal of such a name should be avoided. 4. The application by means of nomencl Note. A generic as to include its type is always so applied specimen. Rules and R Section 1. Pul Article 1. A spec when it has been prin a description, or wit viously published de Note. A recogniz equivalent of a desc of paleobotany and d (a) In the transfe genus to another, th is retained, unless th been previously publi Recommendations: in publishing: 1. In describing på the host and to des host by its scientific 2. To give the etyn names. Article 2. A gen when it has been pr (a) With a generi (or a recognizable fig a binomial specific na (b) With a generi the citation of a prev tion, (c) With a defini one previously publis Note a.-A name citation in synonymy tion. Such a name i to replace one alread Note b.-Of name work and at the same cedence of position having priority. Recommendation: publishing, to give t names when their me |