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SCIENCE. 



insanity, many have a tendency to promote the' most 

 perfect mental and physical development. 



If the Alienist would solve the problem attending 

 the increase of cases of insanity, we would direct him 

 to other sources of the evil than that of civilization ; 

 let him probe the open and hidden vices of great 

 cities ; let him calculate the effect of the indiscriminate 

 use of alcoholic liquors and the pernicious abuse of 

 potent drugs. We regard opium, tobacco, chloral and 

 sewer gas as some of the offending agents which 

 weaken and debilitate the mental powers, rather than 

 the mild educational cause of our public schools or 

 the attending circumstances of student-life. 



Dr. Jewell himself admits the destructive effects of 

 these agents upon the nervous system, but they are 

 classed as due to the influence of civilization. This 

 we think an error, as they are connected with vices of 

 a debased life ; and although insanity may be on the in- 

 crease, we consider it is far from conclusive that to 

 civilization we should attribute the primary cause. 



SCIENTIFIC SOCIETIES IN WASHINGTON, D. C. 



The Biological Society. — Three papers were read 

 at the last meeting, Friday, Feb. 25, as follows : A De- 

 scription of Pronuba yuccasella, by Prof. C. V. Riley ; 

 The Hall Collection of Fossils from New York, by Prof. 

 C. A. White; and Suctorial Prehension in the Animal 

 Kingdom, by Mr. Smiley. Professor Riley's paper was 

 a revision of his communications before the American 

 Association at St. Louis and in other places, concerning 

 a moth, the Pronuba yuccasella, which not only depos- 

 its its eggs in the capsules of the Yucca, but which is 

 also indispensable to the fertilization of the ovaries of 

 that plant. It was remarked by Mr. Lester F. Ward, in 

 commenting upon the paper, that we have here the most 

 wonderful example of commensualism. Professor White 

 is in charge of the duplicate set from the Hall Collection 

 of Fossils sent to the National Museum. His remarks 

 were a brief description of them as they now appear. 

 There are about 1 500 entries, and they represent nearly 

 all the types in the Collection of the American Museum. 

 Mr. Smiley's paper was a description of suctorial organs 

 in the various divisions of the animal kingdom. These 

 organs have in different circumstances, three functions, lo- 

 comotion, anchoring and the seizure of prey. The author 

 has bestowed a great deal of care on his communica- 

 tion and brought together a valuable mass of material. 



The Anthropological Society— The Society met 

 in the main hall of the National Medical College, Major 

 J. W. Powell in the chair. The following papers were 

 read : Amphibious Aborigines of Alaska, by Ivan Petroff ; 

 The Evolution of Marriage Ceremonies and Their Im- 

 port, by Dr. A. F. A. King. Mr. Petroff described his ex- 

 perience among the shore Innuit population of Alaska, 

 from the lower peninsula north to the Yukon mouth. 

 There is water and marsh, mud and swamp everywhere, 

 and the heavens swell the mass by their contribution of 

 fog, rain, snow and sleet. The natives are enveloped in 

 this watery environment the year round and thrive upon 

 it. They even drink enormous quantities of it, not ex- 

 cepting the salt water of the bays and fiords, in their long 

 fishing journeys, Doctor King's paper was an argument 

 to prove that the progress of civilization had the tendency 

 to set aside the laws of sexual relations which exist in a 

 state of nature, such as the survival of the fittest, the ob- 

 servance of natural periods, and sexual selection. The 

 paper was discusssed by Major Powell and Mr. Ward. 



ACTION OF AN INTERMITTENT BEAM OF 

 RADIANT HEAT UPON GASEOUS 

 MATTER* 

 By John Tyndall, F. R. S. 



The Royal Society has already done me the honor of 

 publishing a long series of memoirs on the interaction of 

 radiant heat and gaseous matter. These memoirs did 

 not escape criticism. Distinguished men, among whom 

 the late Professor Magnus and the late Professor Buff 

 may be more specially mentioned, examined my experi- 

 ments, and arrived at results different from mine. Living 

 workers of merit have also taken up the question ; the 

 latest of whom,+ while justly recognizing the extreme 

 difficulty of the subject, and while verifying, so far as their 

 experiments reach, what I had published regarding dry 

 gases, find me to have fallen into what they consider 

 grave errors in my treatment of vapors. 



None of these investigators appear to me to have 

 realized the true strength of my position in its relation to 

 the objects I had in view. Occupied for the most part 

 with details, they have failed to recognize the stringency 

 of my work as a whole, and have not taken into account 

 the independent support rendered by the various parts of 

 the investigation to each other. They thus ignore verifi- 

 cations, both general and special, which are to me of 

 conclusive force. Nevertheless, thinking it due to them 

 and me to submit the questions at issue to a fresh ex- 

 amination, I resumed, some time ago the threads of the 

 inquiry. The results shall, in due time, be communicated 

 to the Royal Society ; but meanwhile, I would ask per- 

 mission to bring to the notice of the Fellows a novel 

 mode of testing the relations of radiant heat to gaseous 

 matter, whereby singularly instructive effects have been 

 obtained. 



After working for some time with the thermopile and 

 galvanometer, it occurred to me several weeks ago that 

 the results thus obtained might be checked by a more 

 direct and simple form of experiment. Placing the gases 

 and vapors in diathermanous bulbs, and exposing the 

 bulbs to the action of radiant heat, the heat absorbed by 

 different gases and vapors ought, I considered, to be 

 rendered evident by ordinary expansion. I devised an 

 apparatus with a view of testing this idea. But, at this 

 point, and before my proposed gas thermometer was 

 constructed, I became acquainted with the ingenious 

 and original experiments ot Mr. Graham Bell, wherein 

 musical sounds are obtained through the action of an 

 intermittent beam of light upon solid bodies. 



From the first, I entertained the opinion that these 

 singular sounds were caused by rapid changes of tem- 

 perature, producing corresponding changes of shape and 

 volume in the bodies impinged upon by the beam. But 

 if this be the case, and if gases and vapors really absorb 

 radiant heat, they ought to produce sounds more intense 

 than those obtainable from solids. I pictured every stroke 

 of the beam responded to by a sudden expansion of the 

 absorbent gas, and concluded that when the pulses thus 

 excited followed each other with sufficient rapidity, a 

 musical note must be the result. It seemed plain, more- 

 over, that by this new method many of my previous re- 

 sults might be brought to an independent test. Highly 

 diathermanous bodies, I reasoned, would produce faint 

 sounds; while highly athermanous bodies would produce 

 loud sounds ; the strength of the sound being, in a sense, 

 a measure of the absorption. The first expetiment made, 

 with a view of testing this idea, was executed in the 

 presence of Mr. Graham Bell ;J and the result was in 

 exact accordance with what I had foreseen. 



The inquiry has been recently extended so as to em- 



* Proceedings of the Royal Society. 



t MM. Lecher and Perntcr, " Philosophical Magazine," January, 1881. 

 "Sitzb. der K. Akad. dcr Wissensch. in Wien," July, 1880. 



JOn the 29th of. November : see " Journal of the Society of Telegraph 

 Engineers," December 8, 1880. 



