R Bunsen—Cabrimetric Investigations. 279 



possessed, as the following consideration shows. Let it be 

 assumed that the amount of ice g, formed during the first seven 

 hours originated in the loss of heat which the water sufiered in 

 order to warm the ice-cylinder from -^° to 0°C., then will the 

 mean temperature, which the ice-cylinder must have had in 

 order to produce the above named weight of ice, result from 

 the equation f =--|^, wherein I signifies the heat of melting 



for water, s^ the specific heat of ice,. and Gr the weight of the 

 ice-cylinder cooled to t°. In this equation only G is unknown. 

 After the termination of the series of experiments in table 1, 

 in order to determine G, the open end of the scale tube was 

 dipped into a weighed glass vessel full of mercury, and, after 

 the ice cylinder had melted and the instmment had been 

 brought again to 0° C, the loss in weight Gi of the mercury 

 vessel was ascertained. The desired weight of the ice-cylinder is 

 Gr = -^, wherein Sg signifies the specific gravity of mercury as 

 0"C.,|3 the weight of melted ice corresponding to one division 

 ''" the scale (e* ' ~~ " ' " , ,. . • 



.--[uation 1). 1^^ v^iuc^ ^ 

 the preceding equation are : 



^=80-03 5,=13-596 5,,=048 



q= 2-13 grm. Gi=61-227 grm. p =0-0008526 grm. 



v= 0-00007733 cubic centimeter. 



By the substitution of these values in the equation there 

 results, as the weight of the ice cylinder used in the observa- 

 ^oQs Q^ 49-65 grm. 



and for its temperature ^= - 6° "95 C. 



The ice cylinder, which had been produced at 

 01 at least —15° C, needed therefore to have po 

 time the instrument was placed in the snow, a temperatu< 

 only, in order to have produced by its warming to 0° C. the for- 

 mation of ice observed during the first seven hours. As from 

 the determination of specific heat communicated beyond, it 

 "lay be concluded that a period of seven hours is far more than 

 sufficient to equalize a difference of temperature of 7° C. m the 

 instrument, it is necessary to ascribe the ice formation which 

 IS visible in the table and which lasted more than 100 hours, 

 to another cause than the one under consideration. Without 

 entering further into the question whether this cause is to be 

 sought for in the air contained in the snow water, as C. Schultz* 

 ^sumes, or whether the passage of the snow to the ^^emi-solid 

 state (firneis), plays therein a part, it may suffice m the first 

 Piace, to give prominence only to those influences determinmg 



* Pogg. Annalen, cxxiTii, 253. 



