Tribune Extras Lecture and Letter Serins. 



THE ACADEMY OF SCIENCES. 



SESSION AT WASHINGTON FIRST DAT. 



CLASSIFICATION OF INSECTS AN AUTOMATON TO 

 PLAY TIT-TAT-TOO HOW AND WHY WE HEAR 

 SOUNDS DWELLING IN THE EAK FLAME PKE- 

 VENTING SOUND FROM PASSING THE STRENGTH 

 AND WEAKNESS OF PINE WOOD. 



[FROM THE SPECIAL CORRESPONDENT OF THE TRIBUNE.] 



WASHINGTON, April 21. The National Academy 

 of Sciences is obliged by the terms of its charter from 

 Congress to hold a meeting in April of each year at 

 Washington. It usually happens that the accumu- 

 lation of papers which the members are anxious to 

 put on record is too great to wait for the annual op- 

 portunity, and that a meeting is called some time 

 during the Fall to throw off the superfluous load. 

 This was the case last year, and led to the meeting 

 in New York in October, which was fully reported 

 at that time in THE TRIBUNE. But the Washington 

 meeting is always regarded as the one of greater 

 consequence; and as the National Academy is the 

 highest scientific body in the country, this session 

 must be considered as of the utmost importance. To 

 it the most eminent men in their special pursuits 

 whom America possesses, contribute the fruit of 

 their painstaking researches, not unfrequently em- 

 bodying in a single paper the labors, not to say the 

 aspirations, of months or even years. 



The mooting was held at the Smithsonian Institu- 

 tion, a temple of science which is the fitting reposi- 

 tory where from all lands and seas curious and val- 

 uable things have been collected, till now it takes high 

 rank among the few great museums of the world. 

 The venerable Prof. Henry, Secretary of the Institu- 

 tion, presided over the deliberations of the Academy. 

 The limited number who by the system of election 

 can be joined to our "immortals" were more 

 largely in attendance than last year at Columbia 

 College. There was a sprinkling of curious visitors, 

 but the Academy makes no bid for popularity. 



Prof. Le Conte was called upon for the opening 

 paper, which was a delicate compliment to a rival 

 institution, as he is the President elect of the Amer- 

 ican Association for the Advancement of Science, 

 a body which has a larger hold on the popular heart 

 than the Academy. 



CLASSIFICATION OF THE RHYNCHOPHOROUS 

 COLEOPTERA. 



BY JOHN L. LE CONTE, M.D. 



Dr. Le Conte's paper began with au allusion to the fact that 

 it ti.o January meeting of the Academy of Sciences in 1867 

 be had opened the subject now under consideration. The 

 j,Toup of insects referred to are exceedingly complex in their 

 ohUiacteristics, and good European entomologists had made 

 frequent efforts to settle their classification. These attempts 



were reviewed historical ly, and the methods and systems were 

 detailed of Schonherr i7> 1833-34 and Prof. Lacordairs in 1863, 

 the latter being somewhat supplementary; of Mr. H. Jekel in 

 1860 ; the remarks of M r. Stiff rain in 1847, and of the work of 

 Prof. C. G. Thompson in 1865, and the careful studies of Dr. 

 George H. Horn, 1873 From the la^t-named work Dr. Le 

 Conte seleets a statemeut concerning the males of some genera 

 having eight and the females seven dorsal abdominal segments. 

 and calls attention to ( he importance and wide extent of this 

 characteristic. He has made a series of dissections of Khyn- 

 chophorous insects, and makes a division of them into three 

 series: (1.) Haplogas ra, having abdomen alike in both sexes; 

 ventral segments noi prolonged upward into a sharp edge. 

 (2.) Allogastra, abdomen dissimilar in the two sexes; ventral 

 segments prolonged r pward, forming a sharp edge. (3.) Het-ero- 

 gastra, abdomen alilxe in botli sexes; ventral segments pro- 

 longed upward to fit into tlr; elytral groove. Many other dis- 

 tinctive characteristics wero given, with a detailed description 

 of the very numerous genera belonging to each of the series. 

 Although princij ally devoted to classification. Prof. Le 

 Conte's paper gave nany points respecting the habits of some 

 of these destructive insects. The Attelabidse and some 

 RynchitidaB provide for their progeny in the Spring. The 

 females roll up the leaves of trees and deposit in each roll an 

 egg. the inside of < he leaf furnishing food to the larva when 

 hatched. Other F in. -hites deposit their eggs in young fruit, 

 the kernel of whi' ;h is eaten by the larva? ; others in undevel- 

 oped buds of tre< , which are thus destroyed. A European 

 species of the Khinomaceridse deposits eggs in the male flowers 

 of the Pinus mi'ritimus, the development of which is thus 

 prevented. The results of years of laborious dissections and 

 study seem to huve been compressed in this paper of Dr. Le 

 Conte, and the exact anatomy and characteristics of a vast 

 number of inserts, many of them the pests of the husband- 

 man or fruit-raiser, were given at great length; but the paper 

 was far too technical for the average reader. 



AN AUTOMATON TO PLAY TIT-TAT-TOO. 



BY PROF, f AIRMAN KOGERS OF PHILADELPHIA. 



This paper described combinations of mechanism for imitat- 

 ing mental processes, illustrated by means of diagrams showing 

 the peculiar requirements of an automaton which should play 

 the game of tit- tat-too against an opponent; the play of the 

 automaton to be a resultant effect of the play of his opponent. 



Among the various classes into which machines may be 

 divided, we find those which have for their object the mere 

 transformation of motion according to various sequences. :is is 

 the case in Blocks, certain portions of moving machinery, and 

 especially calculating machines. In all these the apparatus 

 being constructed according to a certain law, goes through 

 operations .automatically, which resemble to a greater or less 

 extent the operations of the human mind. In the case nf th-i 

 calculating machine it reproduces and extends in a regular 

 sequence the form with which it starts. 



Babbape, in speaking of his analytical engine, ha* suggested 

 that a machine might bo made which would play a game of 

 combination such as draughts, provided the maker of the ma- 

 chine himself could work out perfectly the sequences of th 

 game. He doos not appear to have published anything further 

 on this Kiibject, except to suggest that the child's game of tit- 

 tat-too is the simplest of aU the games of combination, and 

 therefore possible to bo played by an automaton. 



The author of this papej findb that the sequences of this game 

 being rea-lily tabulated, it is possible to arrange a ma.chini; 

 which wi: I follow them, and which will have the power of ap- 

 parently eelecting the course which will lead to success when 

 there aro two ways open to it. It differs from the calculating 



