546 



SCIENCE. 



he read an extract from the Journal of Mental Science, 

 which he claimed showed the awakening interest mani- 

 fested by Europeans in "unconscious states." The 

 Doctor then wandering off to the fall of a Swiss moun- 

 tain and to Astronomy, was called to order, and sub- 

 sided. 



Dr. Spitzka, without desiring to introduce personalities 

 into the discussion, remarked that it was a pity the pre- 

 ceding speaker had not turned back a few pages in the 

 Journal of Mental Science and read the extract relating 

 to the collapse of Dr. Beard's demonstration in England, 

 and how Dr. Beard had failed to come forward with a 

 paper he had announced before a scientific body. As to 

 the paper read that evening, he regretted to say that in- 

 stead of science being behind in its views on the question 

 of alcoholism, it was the paper which was far from 

 being up to the science of the day. He would call the 

 attention of the reader to Magnan's work, in which he 

 would find such of his cases as had the strongest sem- 

 blance to reality, carefully described under the heads of 

 alcoholic stupor and alcoholic epilepsy. As to the hack- 

 driver's case, that was an evident example of a well- 

 established and well-known form of disease, namely — 

 alcoholic paralytic demeniia. He was surprised to find 

 such a common manifestation of alcoholism as tremor 

 reported absent by Dr. Crothers. He was still further 

 surprised to find such ordinary, everyday and character- 

 istic symptoms of chronic alcoholism as delusions of 

 marital infidelity, morbid suspicion, inconsistencies of 

 behavior, stupor and amnesia erected into trance-like 

 states. Nowhere in the paper did the author give any 

 evidence that he made that distinction between Dipso- 

 mania, Chronic Alcoholism and Acute Alcoholic Deli- 

 rium, which was the AB C of our knowledge of the sub- 

 ject. The speaker concluded by regretting that the first 

 time in years that so important a matter was brought be- 

 fore the Society, it was brought forward in so imperfect 

 a form, and coupled with a term " trance," which in the 

 past history of the Society had certainly acquired no 

 good odor. 



Dr. Girdner endorsed the preceding speaker's remarks, 

 and gave an analysis of the ordinary effects of alcohol 

 on the mind, which he referred to dynamic interferences. 

 He concluded by objecting to the acceptation of such 

 views as Dr. Crothers advanced until they could be better 

 substantiated, as their acceptation would involve some 

 remarkable medico-legal consequences. He did not be- 

 lieve that alcoholism, aside from its effect in producing 

 chronic insanity, should constitute an excuse for crime. He 

 thought that a crime committed in a drunken excess 

 should be punished* like any other crime, because the 

 person, by his own agency, put himself in a proper con- 

 dition to commit such crime. 



Mr. Eller, of the New York Bar, stated that the view 

 last announced by the preceding speaker was not a sound 

 one in law ; it was certainly not the one entertained by 

 lawyers. He alluded to the great injustice done by po- 

 lice justices in sending persons to the workhouse on the 

 complaint of any two (possibly) conspiring persons, that 

 such person was a "habitual drunkard." He thought 

 that term required definition. 



Dr. Crothers, in closing the discussion, among other 

 remarks of a general character, stated that our know- 

 ledge of alcoholism was not at all perfect, and that his 

 views were an addition to science, notwithstanding what 

 had been alleged that evening. 



M. Picket has examined seven varieties of steel 

 (chiefly from a Sheffield and a Vienna house) with regard 

 to magnetic, power Arch, des Sciences, August 15). This 

 power he finds to depend on the presence of carbon in 

 the iron, and the aggregation of these substances. One 

 of the two steels giving the best results had ^th percent 

 of carbon. Samples with \y 2 and i>^th percent were 

 i nferior. 



NEW YORK ACADEMY OF SCIENCES. 



October 24, 1 881 . 



Section of Physics. 



Vice-president, Dr. B. N. Martin, in the Chair. 

 Thirty-one persons present. 



Mr. W. Le Conte Stevens read a paper, of which 

 the following is an abstract. 



WHEATSTONE AND BREWSTER'S THEORY OF BINOCU- 

 LAR Perspective. 



For some time after the publication of Sir Charles 

 Wheatstone's essay (') in t 838. on the Physiology of Vision, 

 this subject was studied with much zeal by Sir David 

 Brewster, whose name is permanently associated with the 

 lenticular stereoscope, an instrument now familiar in 

 every household. Although the theories advanced by 

 these two physicists to account for the illusion of binoc- 

 ular relief have since been shown insufficient, their 

 mode of accounting for the estimate of distance as per- 

 ceived in the stereoscope has been quite generally ac- 

 cepted. In 1844, Brewster published an essay ('-') "On 

 the Knowledge of Distance given by Binocular Vision," 

 in which he elaborated and abundantly illustrated the idea 

 that the apparent distance of an object is determined by the 

 intersection of visual lines. The stereoscope had already 

 been explained as an instrument by which rays of light 

 from two slightly dissimilar pictures were made to enter 

 ihe eyes, as if coming from a single object into which 

 they are combined in front, and on each point of which 

 the visual lines could be made to meet. Thus, in Fig. 1 



ZB 



A 



Fig. 1. 



if rays from the conjugate foreground points, A, and A 3 , 

 be deviated by the semi-lenses, they appear to have 

 come from A. In like manner, the background appears 

 at B. If i = interocular distance RL., and a = optic 

 angle, then for the distance of A we have 

 D =' i i cot \ a 

 From this formula it is obvious that D ceases to have 

 any positive finite value when the visual lines cease to 

 converge. 



If the semi-lenses be taken away, and A, and A 2 be 



(>) I'hil. Transactions, 18)8, Part II. 



Reprinted in Phil. Magazine, s. 4, vol., III., April, 1851. 

 (*) Edinburgh Transactions, vol. XV., Part III., p. 360. 



