140 



THE POPULAR SCIENCE MONTHLY. 



Then (in my dream) I dreamt that he tried 

 to frighten me, and make believe he was a 

 ghost, by pushing me down sideways, etc. 

 After that I walied and heard no more." 

 We fancy ghosts as impalpable beings, 

 clothed in white. Blind men can hardly 

 have as distinct an imagination of their ap- 

 pearance. 



A Workmen's Srientiflc Class. — How 

 knowledge may be disseminated by means 

 of local lectures to working-men is illus- 

 trated in a story told by Mr. Roberts, of 

 Cambridge. Two miners, at Buckworth, 

 England, walked four or five miles and back 

 in the evening, after work, to attend the 

 course at Cramlington. Finding others in 

 their village wanting to know something of 

 chemistry, but not able to attend the course, 

 they took to repeating to a class of seven 

 on the next evening the lectures they had 

 heard, and, having supplied themselves with 

 chemicals, repeated the experiments. Mr. 

 Roberts attended one of the meetings of 

 this class at the end of the term, examined 

 the members, and found that they had ac- 

 quired a sound enough knowledge of the 

 subject to pass the regular university ex- 

 amination. The class were this summer to 

 carry on in the same manner a course in 

 physiology, in aid of which they were en- 

 deavoring to procure a microscope. 



Mccbanical Science at the American 

 Association. — The vice-presidential address 

 of Professor J. Buikitt Webb, in the Sec- 

 tion of Mechanical Science, was on " The 

 Second Law of Thermo-dynamics," but was 

 too technical for abstract in these pages. 

 Mr. L. S. Randolph gave an account of his 

 experiments in seeking for an explanation 

 of the peculiar manner in which the stay- 

 bolts between the fire-box and the boiler- 

 shell of steam-boilers had been found to 

 break. He indicated a drawing and bending 

 of the bolts occasioned by the shifting of the 

 plates under chaugcs of temperature as the 

 cause, aided by the corrosive action of the 

 water that might reach the bolts. Mr. Ste- 

 phen S. Ilaight presented a paper on the 

 use and value of accurate standards for sur- 

 veyors' chains, lie exhibited a specimen 

 chain of flattened steel wire, with thermom- 

 eter attached to record temperature, a spring- 



balance tojweigh the tension, and a spirit-lev- 

 el. Professor Davis exhibited a tape which 

 he had found accurate enough for general 

 ■ use in a large range of work in Michigan. 

 j Professor J. B. Webb read a paper on the 

 I lathe as an instrument of precision, in which 

 I he called attention to the desirability of 

 I greater accuracy in instruments of this class, 

 and described some simple methods for mak- 

 ing tests of the degree of error in any par- 

 I ticular instrument. Professor Cooley ex- 

 i plamed a new smoke-burning device. A 

 I committee report was presented and a dis- 

 ! cussion had on the best methods of teach- 

 ! ing mechanical engineering. The object of 

 t the instruction being admitted to be thor- 

 ough preparation in theory and principle, 

 I Professor Thurston said that the training 

 j should be adapted to the work to be done, 

 j and that he therefore favored classification 

 into manual training-schools, schools of me- 

 chanic arts, and schools of engineering. It 

 was asserted by other speakers in the course 

 of the discussion that there are no manual 

 training-schools where a boy can learn a 

 trade before entering the higher schools ; 

 and that the St. Louis and Chicago manual 

 training-schools will not make workmen, and 

 probably not five per cent of their students 

 will ever become workmen. 



Science in Common Schools. — The com- 

 mittee of the American Association on meth- 

 ods of science-teaching in the schools stated 

 that much had been accomplished in the 

 investigation, in which many associations, 

 schools, and persons had interested them- 

 selves. The committee of conference with 

 foreign associations in reference to an in- 

 ternational convention of science associations 

 had conducted an extensive correspondence, 

 and the subject was to be brought before 

 the British Association at Aberdeen. An 

 endowment fund of twenty-five thousand 

 dollars had been given to the scheme by 

 Mrs. Elizabeth Thompson, of Stamford, Con- 

 necticut. The committee was continued as 

 the " Committee on International Scientific 

 Congress." The committee on the encour- 

 agement of researches upon the health and 

 diseases of plants reported that at its sug- 

 gestion the Commissioner of Agi'iculture 

 had appointed 5Ir. F. L. Scribner, of Girard 

 College, Philadelphia, to take charge of a 



