er ig . . « Markowitz’ failure to find detailed reports in print is puzzling. That he should base his arguments on the minor Chiles-Whitted case (of which it is true that my evaluation is at variance with Hynek’s) or such a brief observation, made under unfavorable conditions, as the Tombaughcase, tends to indicate that he is not really interested in the best documented sightings; on the contrary, he is deliberately selecting borderline cases in an effort to cast doubts on the validity of current official and private attempts at system- atic data-gathering. Otherwise, how can we understand that the Forcalquier photographs (taken by a professional astronomer) or the observations made at Toulouse and Mount Stromlo observatories, or the Loch Raven Dam and Socorro cases, all of which are exten- sively documented in print, should have escaped his attention? He goes as far as stating that no unexplained physical trace has ever been left after the observation of an unknown aerial phenomenon, while one of the books he quotes in his bibliography describes at length the investigations conducted by Soviet physicists at the site of the Siberian explosion in 1908, which come very close to meeting the conditions Markowitz himself has set for “evidence.” Elsewhere, commenting on my survey of the observations of unknown celestial objects gathered and studied by Le Verrier, he kindly reminds me that the intra-Mercury planet theory is an impossibility, as if I had ever suggested that the objects in question were such a thing. Thus, Markowitz is guided by one and only one idea: that one may not consider the “intelligent control” hypothesis unless one is willing to abandon entirely the rational processes upon which science is based. It is a disturbing fact that such grossly irrational arguments should still enjoy popularity in the scientific world... . JACQUES F. VALLEE Department of Astronomy, Northwestern University, Evanston, Illinois 60201 . . . If scientists avoided topics which involve possible violations of the inviolable laws of physics we should have unsung memorabilia like these: “Marie, this phosphorescence violates the First Law;Iet’s study barium sulfate instead.” “Xenon can’t react; it has a closed shell. Ask any theoretician.” ‘“Conser1266 vation of parity is one of the immu- table laws of physics, therefore it is impossible that...” I doubt very much that UFO’s are under extraterrestrial control, but if they were so controlled I am sure we primitive bipeds could prove the contrary by citing our laws of physics. THOMAS R. P. Giss, JR. Department of Chemistry, Tufts University, Medford, Massachusetts 02155 Markowitz has closed the door on UFO’s and space travel by showing that interstellar vehicles can never have visited Earth because neither he nor any Congressional committee has seen one. Only unreliable witnesses see UFO’s which might be extraterrestrial. (An unreliable witness is anyone who reports a UFO that isn’t an obvious natural or aerial phenomenon.) The scientific journals would, of course, be full of observational accounts, if any credible ones were presented, and scientists would be as eager to study them as they were Velikovsky’s work 15 years ago. The evidence against UFO's as space vehicles, based on Simon Newcomb’s recent (1895) proof that an intra-Mercury planet cannot exist, is as convincing as Newcomb’s dem- onstration, following accepted physical laws, that aircraft can’t fly... . PHitie C. STEFFEY 2402 Third Street, Santa Monica, California While reading Markowitz’ article, I could not help thinking about some words I believe were written by Isaac Asimov: that when a respected scientist said something was probable, he was probably right, and if he said that something was impossible, he was probably wrong. IsapEL R. A. Garcia 152-72 Melbourne Avenue, Flushing, New York 11367 I was amused and somewhat shocked by Markowitz’ reference to Aristotle’s “Physics” and “Metaphysics.” The idea that “metaphysics” is equated with the notion that “the laws of physics are not valid” is not only misleading as it relates to Aristotle, but threatens to make the philosopher who spe- cializes in metaphysics some sort of buffoon. . GEORGE COHEN Philosophy Department, Long Island University, Brooklyn, New York 11201 Smoke-Filled Friendships As the first three couplets of the following verse attest, I share Turbeville’s aversion to tobacco smoke (Letters, 20 Oct.), though, as the last couplet shows, I do not often express my objections. A cigarette’s what the smoke from all goes From wherever it is to a nonsmoker’s nose. Smokers are who,if at parties they’re there, I must later change clothing and shampoo my hair. A nonsmoker’s who, when it’s too thick to see, If you hear someone coughing, it’s probably he. Friendship is what, though I gag, weep, and choke, I would much rather have it than absence of smoke. Smokers often ask a stranger, “Do you mind if I smoke?” If the stranger does not smoke, he probably minds, and is then faced with the poor choice of being rude or perjuring himself. I suggest that smokers ask instead, “Do you smoke?” and refrain if the answer is “No.” MILTON HILDEBRAND Department of Zoology, University of California, Davis 95616 Buffalo River Endangered Carter’s article, “Dams and wild rivers: looking beyond the pork barrel” (13 Oct., p. 233), is most timely. Here in Arkansas we have reason to be keenly aware of the dam-building pork barrel through our efforts to preserve the beautiful Buffalo River in the Ozarks of northern Arkansas. The Buffalo is one of the few free-flowing streams remaining in the state. For years it has been threatened with impoundment by the Corps of Engineers. The National Park Service recommends preservation of the Buffalo as Buffalo National River. The great majority of the people of Arkansas support preservation of the Buffalo. Bills are pending in the U.S. House and Senate which would establish the Buffalo National River, but these have not yet come up for consideration. Despite the growing realization of the economic and ecological losses resulting from unnecessary impoundments, strong pressures for unjustifiable projects continue. L. ARCHER Ozark Society, Box 38, Fayetteville, Arkansas 7270] SCIENCE, VOL. 158