AMERICAN INSTITUTE. 57 



members ready to give their views, wbich, however, added nothing to the 

 information already possessed on the subject. 



Mr. Babcock gave an interesting account of Stillman & Webster's mode 

 of superheating, which is now employed at the Mystic Co. Works. There 

 is a superheating chamber, which receives the products of combustion 

 directly from the furnace. This chamber is twelve feet long. There are 120 

 tubes one and one-half inch diameter, making in all 125 feet. Through 

 these pipes the steam passes to be superheated. The best and most impor- 

 tant part of the arrangement is the "thermostat," by means of which the 

 degree of superheating is automatically determined. It consists of a vessel 

 of water with a diaphragm dividing it into two parts ; one being connected 

 with the boiler, the other with the superheating chamber. The diaphragm 

 is connected with a lever, which can be so weighted as to determine the 

 exact amount of superheating, by controlling the damper governing the 

 amount of heated gases admitted into the chamber. It has been found to 

 regulate within two degrees, and never has exceeded a variation of ten 

 degrees. 



Mr. Lamed remarked that, from the data given, it was evident that the 

 percentage of heating surface (about forty feet in 600 feet), which was 

 given: by the superheating tubes, was far less than the percentage of power 

 (about twenty-five per cent.) gained. 



Mr. Melrose gave his experience of locomotives, using superheated steam, 

 in which the extreme dryness caused the parts to wear out rapidly. 



The Association adjourned to Thursday, the 8th inst. 



Polytechnic Association of the American Institute, 



March Sth, 1860. 



Professor Mason, Chairman. John Johnson, Esq., Secretary pro tern. 



The Chairman asked Mr. Hills to come forward and introduce the sub- 

 ject of " Steam Heating." The gentleman declined speaking at that 

 moment, but would bring it before the club at their next meeting. 



The Chairman said that the subject was 



"adulteration of food and drinks." 



Mr, Bruce read a piece taken from the Tribune, relating to Dr. Hiram 

 Cox, and his lectures on the liquors. 



These liquors were described as the principal cause of insanity, and as 

 not containing more than seventeen per cent of alcofiol — the balance being 

 water, strengthened by sulphuric acid, nitric and prussic acid, nux vomica, 

 Guinea pepper, and other deadly poisons, one pint of which would kill any 

 man. 



Dr. Stevens read a short paper, which he did not profess to render 

 scientific, but he vouched for the statements it contained, as embodying 

 facts by his own experience. He stated that sugar was adulterated with 

 Westchtester county marble ; coffee with burnt beans ; tea had old tea 

 leaves from Water street, and clover leaves from hay mixed with it. The 



