Chemistry and Physics. 495 



this compound. Both bodies on addition of bromine give the 

 same tetrabromide CH 3 . CBr 2 . CBr 2 . CH 3 . — Ann. Chem. Pharm., 

 ccl, 224, 230, Jan., 1889; Nature, xxxix, 467. G. f. b. 



5. On Aluminum acetyl-acetonate. — Combes has recently pro- 

 duced an organic aluminum compound of some interest, since it 

 seems likely to settle the disputed question of the valence of this 

 metal. This compound is aluminum acetyl-acetonate, a white 

 crystalline solid melting at 193°-194° and distilling unchanged 

 at 314°-315°. Two density determinations by V. Meyer's method 

 in nitrogen and at the temperature of boiling mercury gave values 

 corresponding to the molecular masses 325-5 and 324-2; the mole- 

 cular mass of A1(C 6 H 7 2 ) 3 being 324*5. Hence the triad formula 

 is the only possible one even at this low temperature. There was 

 no trace of decomposition. — (J. P., cviii, 405, Feb., 1889; Pull. 

 Soc. Chim., Ill, i, 343, March, 1889. g. f. b. 



6. Connection of Pegnaidfs results upon the toeight of gases. — 

 J. M. Crafts, following up the suggestion of Lord Rayleigh in 

 regard to the effect of the presence of the atmosphere upon the 

 vessel in which the gases were weighed by Regnault, finds the fol- 

 lowing corrected values for Regnault's results for density : 



Corrected value for 

 Regnault. Corrected. weight of a liter. 



Air 1-00000 1-00000 1-29349 



N 097137 0-97138 1-25647 



H 0-06977 0-06949 0-08988 



O 1-10564 1-10562 1-43011 



C0 2 1-52910 1-52897 1-97772 



— Comptes Pendus, cvi, p. 1662-64, 1888. J. t. 



7. Pon spectrum. — H. Kayser and C. Runge have issued a 

 paper giving a catalogue of 4500 lines of iron based upon the 

 absolute wave-length determinations of Rowland and Bell. Each 

 line is characterized in the catalogue by its peculiarities as to 

 sharpness and reversed nature, etc. The wave lengths were 

 measured by Rowland's gratings and the limit of accuracy is 

 O'OlyU//. The authors believe that the iron lines will serve as 

 reference lines for other workers in spectrum analysis. They hope 

 to connect the spectra of other elements to the iron spectra by 

 certain equations. — Peibldtter Annalen der Physik und Chemie, 

 No. 2, p. 78, 1889. J. t. 



8. Electrical currents arising from deformation. — The subject 

 of the effect of torsion of bending and pressure upon the produc- 

 tion of thermo-electric currents has been exhaustively studied by 

 various writers. Ferdinand Braun has lately studied the sub- 

 ject anew and finds a remarkable example of these phenomena in 

 nickel. — Annalen der Physik und Chemie, No. 5, pp. 97-127, 

 1889. J. T. 



9. Electrical dilatation of quartz. — J. and P. Curie continu- 

 ing their work upon this subject have constructed a manometer 

 consisting of plates of quartz which are connected to a quad- 

 rant electrometer and are subjected to pressure. The sensitive- 

 ness of the apparatus is very great. With crystal plates having 



