100 



TRANSACTIONS OF THE 



7 V' ' 



J uluison 



Patent Self-regulating Windmill. 



Johnson'' s Wind Mill. 

 F. G. Johnson, Brooklyn, L. I. The best windmill. 



^Silver medal awarded. 

 Specimens of Jirtijicial Stone. 

 The American Artificial Stone Company, 340 Broadway, N. Y. 

 It is composed of sand, plaster, and blood — three-fourths sand, 

 and one-fourth plaster, (or sulphate of lime,) moistened with 

 blood. Is capable of being moulded into the most elaborate 

 architectural ornaments, copies of sculpture, suitable for park 

 and garden ornaments, monuments, &c. It assumes the charac- 

 ter of stone in a few hours, without baking, or any other speci- 

 fic treatment, after being moulded. A few days hardening en- 

 ables it to resist a considerable crushing pressure, and renders 

 it fit to take its place, with suitable care, among the ordinary 

 materials of a city building, and to withstand the action of the 



