652 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



American Institute Polytechnic Association, \ 

 April 28, 18G4. ) 



Chairman, Prof. S. D. Tillman; Secretary, Mr. B. Garvey. 



Windmills. 



Mr. T. B. Fields, of Nantucket, Mass., exhibited the model of a windmill. 

 Its novelty consisted in the use of balanced sails, moving horizontally 

 around a common axis, each sail having- also an independent rotation, by 

 which the edge is presented to the wind when moving against it, and the 

 face when moving with it. 



The Chairman remarked that the model displayed some ingenuity, but 

 the objection made to feathered paddle-wheels would apply to this case. 

 The shape of the sails might be impioved, by substituting, for the rect- 

 angular, the triangular form, by which the base of the sale would have the 

 slowest and its apex the swiftest motion; thus, the extent of the surface of 

 sail varying inversely as its velocity, the force of the wind would be more 

 equable upon the whole length of the arm. The wing of the bird is con- 

 structed on this principle. It is narrowest at the point of greatest motion, 

 The windmill is of use where a small power is required, which need not 

 act continuously. It is clumsy, but cheap and convenient, because it 

 requires no replenishing or superintendence when its sails are made so as 

 to close as the wind increases in velocity. Hence considerable ingenuity 

 has been shown in making the windmill automatic or self-adjusting in high 

 •winds. Mr. Francis Peabody, a prominent citizen of Salem, has made 

 many expensive experiments for the purpose of perfecting a wind turbine 

 wheel which can be used for farm purposes, and on the prairies of the West, 

 •where water-power and fuel fur making steam cannot be readily obtained. 



Thomas Blanchard. 



The recent death of Blanchard was alluded to by Dr. Rowell, who 

 recounted some of the achievements of this distinguished American inventor. 

 He described one of the most useful of his labor-saving machines — the 

 lathe for turning irregular forms, which copies in reduced size if required. 

 A very small marble bust of Webster was exhibited in an unfinished state, 

 as taken from the machine, to illustrate the perfection of the work up to 

 the line where it ceased. 



Mr. Stetson also spoke of Blanchard as the inventor of the tack machine. 



The Chairman added that the loss of prominent literary men called forth 

 eulogies from their cotemporaries, and it was very proper for this Associa- 

 tion! to notice the demise of eminent mechanics. He who has given new 

 forms to matter or new directions to force, by which the material condition 

 of man has been improved, has done a real service to his race which may 

 continue in full effect long after the inventor is forgotten. The absolute 

 progress of civilization depends on discovery and invention. It was 

 impossible to carry on a war like the one in which we are now engaged 

 without the aid of the great inventions brought forth first in our own 

 country. Let us always trace true power to its true source, and pay a 

 becoming tribute to the memory of a great inventor. 



The following scientific summary was presented by the Chairman: 



