Augtist 19, 1880] 



NATURE 



379 



0-0486S 



0"00292 



0-04539 

 0*00292 



o'osi6o 



o '0483 1 



,Ve have then the apparent [compressibility 



of water in glass at 2" 5° C 



lAdd compressibility of glass 



True compressibility of water at 2'5° C. 

 And the apparent compressibility of water 



at 12-5'' C. is 



lAdd compressibility of glass 



True compressibility of water at la'S" C. ... 



Gra=si gives the following values for the true compressibility 

 of water at various temperatures : — 



At i'S°C 0-0515 



At 4'i° C o"0499 



Mean 0*0507 



i At 10-8° C 0-0480 



I At 13-4° C 0-0477 



Mean 0-047S 



(My results agree very closely with these. 



I Before concluding I would call attention to a very curious 

 iphenomenon which I have never seen noticed, namely, the 

 Ipccidiar noise which accompanies the relief of pressure in a 

 [mixture of ice and water. 



In comparing the Piezometer K No. 4, in melting ice with the 

 manometer at 12-5° C, I proceeded gradually from lower to 

 Ihigher pressures. When the pressure which was relieved was 

 1 1 00 or 120 atmospheres, I thought I noticed a slight noise. On 

 •raising the pressure higher the noise became more and more 

 (distinct, untU when the pressure relieved was over 200 atmo- 

 spheres, it was distinctly audible at a distance of 5 feet or 5 feet. 

 It resembles the noise produced by bending a piece of tin back- 

 wards and forwards, and is markedly intensified by accelerating 

 Ithe relief, just as the noise made by blowing off steam is intensified 

 by enlarging the outlet. When the relief valve is opened very 

 carefully it whispers gently but very distinctly, till the pressure 

 js all down. If opened comparatively briskly, but still with 

 ^great care, the noise is comparatively loud but more rapidly used 

 jup. I forbear making any reflections until I have been able to 

 Study this phenomenon more closely. 



Pieces of clear ice which had been subjected to high pressure 

 in the receiver were finely laminated ui parallel planes. In each 

 plane there was a central patch furrounded near Uie sides of the 

 clock by a ring of spherules. 



"' The annexed figure gives an idea of the arrangement in 

 1 plane of lamination ; the size of the spherules is greatly 

 exaggerated. 



The lamination of ice by pressure in one direction is well 

 cnown. I am not aware that its production by pressure in all 

 lirections has been noticed. I hope to pursue my observations 

 )n this subject. J. Y. Buchanan 



THE CONGRESS OF BOHEMIAN PHYSICIANS 



AND NATURALISTS 

 "pHE first Congress of Bohemian Naturalists and Physicians 

 -"■ met at Prague on May 14 last. More than 400 members 

 net under the presidency of M. Krejci, M. Eiselt, M. Koristka, 

 ,nd M. Studnicka. The first general meeting was opened by 

 A. Krejci, Professor of Geology, who delivered an inaugural 

 iddress " On the share of the Bohemian Nation in the Develop, 

 ioent of Natural Science." He showed that not only Bohemian 

 vorkers in science were in the field up to the seventeenth century, 

 |iut that when the Bohemian nation, after two centuries of 

 oolitical and national slavery, awoke to life again, it very soon 



took its part in the progress of natural science. The names 

 of Purkyne, Rokytansky, Skoda, Bohdalek, Pitha, Blazina, 

 Safarik, Celakovsky, Fric, lu'ejci, Helmhacker, and of many 

 others, are known even beyond the boundaries of Bohemia. 

 Many obstacles were placed in the way of these promoters of 

 science ; they were not assisted by Government, and even tlie 

 ancient university of Prague was, and indeed is, almost exclu- 

 sively German. But in spite of all difficulties scientific progress 

 went oti steadily, and at present the number of workers in 

 science;is very fair. Knowing the cosmopolitan character of 

 science, the Bohemian nation values equally the progress made in 

 England, France, Germany, Italy, and Russia ; it wishes only 

 that its own share— if proportionately small— may be recognised 

 by others. The great languages of the world are like the sea, 

 which carries the ships and steamers of all nations ; but the 

 languages and literature, of small nationalities— of the Danes, 

 Swedes, Dutch, and Bohemians — resemble so many rivers irrigating 

 and fertilising the continents by which the sea is surrounded. 



On May 15 and 17 sectional meetings took place. On the 

 l6th the members visited the village Chuchel, where Prof. 

 Krejci explained to them the very interesting distortions of the 

 Silurian strata on the left bank of the river Vltava (Moldau). In 

 the evening of the same day the members assembled at a banquet, 

 where especially the healths proposed by Prof. Safarik were 

 heartily responded to. He spoke first of the progress of science 

 in Bohemia and its relation to scientific investigation in England 

 and France ; he then proposed the health of the distinguished 

 Russian naturalists, referring chiefly to Mendeleeff, ButlerofT, 

 Meushutkin, Chebysheff, Shecheneff, Mechnikoff, and Kowa- 

 lewski ; finally he drank to the Nestor of palteontological research, 

 to Joaquin Barrande, whojat Prague has carried out the chief 

 part of his scientific work. 



In the first section (medicine) papers were read on purely 

 professional subjects. 



The second section was devoted to mathematics. Besides 

 several mathematical papers Prof. Augustin spoke on cyclones 

 and anticyclones ; M. Doubrava read a paper on electricity ; 

 M. Domalip explained the action of a magnet on a cm-rent of 

 electricity traversing a rarified medium ; Prof. Charles Zengef 

 gave an account of his method of constructing achromatic lenses 

 by means of a combiuation of crown-glass and certain liquids. 

 Excellent microscopic photographs made by the aid of these 

 lenses were shown. For astronomical purposes lenses \-\'ith an 

 opening of 2 inches and a focal distance of only 9 inches have 

 been constmcted according to this method with complete 

 success. 



In the third section (Natural Science) the following 'papers 

 were read : — Prof. Boricky, on the structure of the Bohemian 

 porphyries. He showed that they frequently contain the mineral 

 "cordierite," which hitherto had not been^ found in Bohemia. 

 Accordmg to Prof. Boricky a great part ' of the] Bohemian 

 porphyries must be classed as siliceous porphyrites. Prof. Fric 

 demonstrated a new genus of the ganoids found at Kounova, 

 near Rakovnik. This fish resembles the genus Palajoniscus, but 

 its scales are very different. He gave to the new genus the name 

 of Trissolepis kouncmensis . 



M. Bayer gave a report on the characters of the skulls of some 

 batrachia. Comparing the skull of the genus Pelobates with 

 that of other genera, he found that the skull of Pelobates difliers 

 essentially from all others, and that this genus does not form the 

 connecting link between the Ranidje and the Bufonida;. M. 

 Hellich read a report on the genital apparatus of the genus 

 Cypris. He supplemented the data given by Zenker, and corro- 

 borated in a certain sense the new observations of Weissmann. 

 A series of plates belonging to a new work on Bohemian creta- 

 ceous Echinodermata ^^•as shown by Dr. Ottomar Novak, and 

 their peculiarities were explained. M. Ladislav Duda gave a 

 preliminaiy account of the anatomy of the Bohemian hemiptera, 

 especially of the section Scutata. He has discovered on the fore 

 feet of these insects a comb-like apparatus, by means of which the 

 insect cleans its tentacles. In Bohemia as yet 401 species of hemi- 

 ptera have been found. Prof. Boricky showed to the members 

 many interesting novelties in mineralogy, as, e.g. , the Rosslerit, 

 a mineral of \Ahich as yet only three specimens are known. Dr. 

 Vcjdovsky exhibited the second part of his work on the com- 

 parative morphology of the annelids, containing a new system of 

 the Oligochccta and their anatomical details, together with their 

 affinities to the Turbellaria and vertebrata. Dr. Vejdovskj^ pro- 

 poses the following arrangement of the new families of the Oli- 

 gochsta : — (i) Amedullata (Aeolosoma), (2) Chsetogastrida, (3) 



