PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 597 



The gun will use a spherical shot of 1,000 lb., or a shell of 750 lb. If 

 the gun is rifled it is thought it will carry a shot of one ton weight. The 

 charge of gunpowder will weigh from 80 to 100 lbs. This gun is said to 

 be the largest in the world, and to Pittsburgh belongs the honor of pro- 

 ducing it. Report says it is to be placed on some of the defences of the 

 harbor of New York. 



Prizes. 



The French Academy of Science, offer a prize of a gold medal, value 

 3,000 francs, for the best paper on " The Comparative Anatomy of the 

 Nervous System of Fishes;" latest day for the reception of papers, Sept. 

 1, 1864. Also 3,000 francs for the best paper on " The Production of Hy- 

 brid Animals by means of Artificial Fecundation;" latest day December 31, 

 1865. Also three prizes, in all amounting to 30,000 francs, for papers on 

 certain medical and surgical subjects. Competition for all these prizes is 

 open to all the world. 



An article on "the Manufacture of Chocolate" was read, and called 

 forth remarks from several members. 



Dr. Rich stated that chocolate has been made in this city of such fine 

 quality as to bring orders for it from France, which has always been con- 

 sidered foremost in this manufacture. 



Articles on "confectionery," "the preservation of meats," and "the 

 frigate Re d'ltalia," were read, which are too long to insert. 



Great Guns. 



In regard to casting great guns, Mr. James L. Jackson doubted the prac- 

 ticability of making perfectly sound castings of such great size. He had 

 examined some fragments of large guns with a glass and found them 

 very porous. 



Mr. Fisher said this question of the even quality of large castings was 

 an important one. He inquired whether any one could give information 

 regarding the quality of the interior of iron chilled some time since at the 

 Novelty Works. 



Mr. Maynard replied that the mass of iron alluded to (a solid 5 feet by 

 1) was not chilled in the furnace ; it had been poured into a ladle to be 

 used with other meltings, to form a bed-plate for a steamship, but when 

 the men were ready to pour, it was found to be chilted. It was said that 

 it would not pay to break it up; but the breaking was afterward accom- 

 plished, and on examining the fragments he was surprised to find its tex- 

 ture even and consistent to the center. The large guns alluded to have 

 not so long a range as may be supposed. The effective work now being 

 done at Charleston is by 12-pounders, and not by 200 or 300-pounders. 



The ,f ubject was further discussed by Messrs. Rowell, Bartlett, and 

 Rosevelt. 



After some inquiries from Mr. Root on the subject of specific heat, the 

 selected subject was taken up. 



The Necessity for a Reform in our Weights and Measures. 



The chairman remarked that this subject has of late commanded the at- 

 tention of leading men in every civilized country. There is an increasing 



