444 SCIENTIFIC RECORD FOR 18a4 



(laraental units used are the centimeter, gram, minute. {II Nuovo Ci- 

 viento, XIII, 104 ; J. Phys., December, 1884, IT, iii, 555.) 



Bunsen has investigated the condensation of carbon dioxide gas on 

 the surface of glass. The glass employed was the fine-spun variety 

 used in weaving. The space occupied by 150 grams was only 100 c. c. 

 The length ot filament was 62 geographical miles and its surface 23 

 square meters. The spe(;ific gravity of the glass was 2.50500. The ap- 

 paratus consisted of a graduated glass tube, closed above by a stop- 

 cock ; above this is a length of the same tube, in which the spun glass 

 is placed, and which is closed above by a second stop cock. The whole 

 is placed over a mercury cistern, and the lower part filled with dry QO^. 

 The upper part is then exhausted, and the experiment commences by 

 opening the communicating stopcock. At the end of a given time the 

 pressure of the gas is determined anew, and from this the weight of the 

 gas which has been condensed is readily calculated. Bunsen's experi- 

 ments began on the 20th of April, 1880, and at the end of three years 

 the condensation did not seem to have terminated. During the first 

 year it was 49.21 c. c, during the first two years 57.94 c. c, and during 

 the three 09.98 c. (;., or for the three years 5.135 c. c. per square meter. 

 Granted that capillary attraction can be perceived, as Quincke states, 

 at a distance of 0.000005"™ from the surface, the 5.135 c. c. condensed 

 on a surface of 10,000 sq. cm. would occupy a space of 0.05 c. c. and 

 have been condensed by a pressure of 102.7 atmospheres. Since carbon 

 dioxide is liquid at 57.5 atmospheres at the temperature of the experi- 

 ments, there can be no doubt that the surface of the glass was covered 

 with a layer of liquid carbon dioxide. ( Wied. Ann.^ xx, 545 ; FhU. 

 Mag., March, 1884, V, xvil, 161 ; J. Fhys., June, 1884, II, in, 262.) 



Blondlot has considered the influence of electrification on the maxi- 

 mum tension of a vapor in contact with its liquid, and concludes that 

 the maximum tension of the vapor in contact with this electrified sur- 

 face is smaller than it would be if the surface was not electrified, by an 



amount represented bv 2-/^^ ' ,in \vliich/>. represents the electric surface 



density and - the ratio of the densities of the vapor and the liquid. 

 (J. Phys., October, 1884, II, iii, 442.) 



ACOUSTICS. 



Martini has studied the phenomena of the production of sound by the 

 flow of liquids. His apparatus consisted of a vertical tube either of 

 glass or metal, within which was a metallic disk perforated at its center 

 with a hole, the diameter of which was equal to the thickness of the 

 plate; The production of the sound is determined by the periodicity 

 of the flow, the tone produced being either the fundamental note of the 

 liquid column or one of its harmonii-s, according to the ])ositiou of the 

 regulating cock. The sounds produced seem like those of a closed pipe. 



