PEIZE-QUESTIONS OF SCIENTIFIC SOCIETIES, 439 



prize-essays, tbe period for the reception of essays terminating on the 

 1st of January, 1876 : 



I. Give the' results of exact investigations on the dissolving effect of 

 water and water charged with carbonic acid on gyj)suni, limestone, and 

 dolomite at different temperatures and under different pressures, and 

 in cases where sea-salt and other abundant soluble salts are present. 



II. Give the results of exact determinations of the dissolving effect of 

 water and of water charged with carbonic acid on silica and the most 

 common natural silicates at different temperatures and under different 

 pressures and in cases where sea-salt and other widely-diffused soluble 

 salts are also present. 



III. Give the results of a new study of the structure of the viscera of 

 mammals, especially in regard to the epithelial covering in the different 

 portions of the renal tubes. 



lY. It appears from recent investigations that the peptones of many 

 albuminoid materials are composed of substances now known in part 

 and in part unknown. Eequired a critical review of these investiga- 

 tions, sux^plemented by personal researches on the same subject. 



V. Give the exact determination in Weber's units of the resistance of 

 a column of mercury one meter (39 inches) long, and a square millimeter 

 (1 square inch) in section at 0°, (32 F.) All the steps relative to this 

 determination should be given to as complete an extent as possible. 



VI. To increase by means of careful experiments our knowledge of 

 the relation between the two kinds of electrical units, electro-magnetic 

 units and electro-static units. All the steps in this determination should 

 be presented as fully as possible. 



VII. Eequired new experiments in regard to the influence of pressure 

 on chemical action. 



The society repeats the following c?uestions, the period of competition 

 for which expires January 1, 1875 : 



I. Give for ten varieties of glass of known chemical composition, 

 1st, the co-efficients of expansion between 32° and (at most) 212° F., 

 noting the influence of temper and the state of tension 5 2d, the coefli- 

 cients of elasticity, with exact reports of temperature ; 3d, the indices 

 of refraction for at least ten points taken over the entire extent of the 

 spectrum ; also carefully noting the temperature. The gold medal and 

 150 florins. 



II. Does the co-efficient of expansion of steel vary with the degree 

 of temper; and can empirical laws be determined in regard to the con- 

 nection of these two elements ? 



III. Do experiments show a connection between the diffusion of 

 liquids separated by porous partitions and other phenomena, such as 

 capillarity, &c. ? 



IV. Determine the co-efficient of expansion of at least three liquids of 

 simple composition, following the method by which the absolute expan- 

 sion of mercurj has been determined. 



