REPORT OF THE MECHANICAL SECTION. 39 



of appreciation by the Institute of the scientific and mechanical 

 skill exhibited by him. 



2d. " Cregan's improved calipers." 



This instrument was neatly made and finished, and differs from 

 those in common use, in having the points so arranged as to be 

 exactly opposite to each other when closed. This was effected by 

 having one of the limbs double, united at the points by a pin serv- 

 ing as an axle to a small roller, this small wheel or roller constitu- 

 ting one of the points. 



Your committee came to the conclusion that the position of the 

 points might be some advantage, and was a novel feature in cali- 

 pers, but objected to the wheel, which, requiring to revolve with 

 freedom on its axle, destroyed that nicety of measurement which 

 mechanics' expect from such an instrument. Under these circum- 

 stances your committee do not feel called upon to recommend any 

 award, but would compliment the neat workmanship displayed in 

 the manufacture of the tool. 



3d. "J. R. Fergusson's heating and ventilating system for build- 

 ings and refrigerators." 



This system consisted in making the walls and roof of the apart- 

 ment containing the stove or heater double, and introducing the 

 cold air into the double skin of the roof at one side; from the roof 

 and communicating with this jacket, a series of tubes descending 

 to within a few inches of the floor; the cold air passes down 

 "hrough these tubes into the hot chamber, having previously taken 

 up whatever heat was being radiated into the jacket from the inner 

 ^in of the chamber. The inventor claimed that a great saving 

 of fuel was thus efiected, and that the air became thoroughly heated 

 without the disagreeable odor which usually arises from furnaces 

 wien highly heated. 



The inventor not having exhibited a working model, and being 

 unable to exhibit his system in successful operation, your com- 

 mittee, while acknowledging the apparent merit of some of its fea- 

 tu:es, do not feel justified in making any recommendation for a 

 meial. 



4th. " Shaw's patent sash fastener," 



This your committee considered ingenious, but a little complica- 

 ted, effecting perfectly the intended purpose, however ; but as no 

 evidence as to durability was advanced by the inventor, they do 

 not consider that at this time a medal should be awarded. 



5th. " Wood's photographic engraving." 



This invention being evidently (from the samples exhibited) still 

 incomplete, your committee prefer at this stage not to pass an opin- 

 ion upon it. 



