Vni CONTENTS OP VOL. XXXI. — THIRD SERIES. 



Page 

 Prof. Sir W. R. Hamilton on Quaternions ; or on a New Sy- 

 stem of Imaginaries in Algebra (continued) 511 



Mr. J. H. Gladstone's Contributions to the Chemical History of 



Gun-Cotton and Xyloidine 519 



Proceedings of the Royal Astronomical Society 528 



On Osmiamic Acid, by MM. J. Fritzsche and H. Struve .... 534 

 On the Preparation and Properties of some Osmiamates, by 



MM. Fritzsche and Struve 535 



On Sulphato- chloride of Copper, — a New Mineral, by Arthur 



Connell, Esq '. 537 



On the Formation of Valerianic Acid, by M. Therault 538 



Note on the Measurement of the double Sulphates of Zinc and 



Soda, and of Magnesia and Soda, by W. H. Miller 540 



Native Carbonate of Nickel 541 



An Examination and Analysis of the " Nadelerz," or needle 



ore of Bismuth, by E. .T. Chapman, Esq 541 



Action of Anhydrous Phosphoric Acid on Ammoniacal Salts, by 



M. Dumas 544 



Meteorological Observations for October 1847 545 



Table 546 



Index 547 



PLATES, 



I. Illustrative of Sir D. Brewster's Paper on the Modification of the 

 Doubly Refracting and Physical Structure of Topaz, by Elastic 

 Forces emanating from Minute Cavities. 



II. Illustrative of Prof. Wartmann's Fourth Memoir on Induction. 



III. Illustrative of Sir D. Brewster's Paper on the Existence of Crystals 



with different primitive forms and physical properties in the Cavities 



of Minerals. 



Erratum in Mr. Sylvester's paper, p. 189 

 Line \^,for Ti'xyz read D'uviv. 



Errata in Sir Graves C. Haugaton's paper, vol. xxx. p. 437. 

 P. 445, in the thirteenth line from the bottom,/or M024 read 1,1024. 

 ninth line from the bottom,/o;- 256° read 256. 



— 456, in the third line from the bottom,/o;- Hare hair read Horse hair. 



— 518, in the thirteenth line from the bottom,/or oxide of hydrogen read 



protoxide of hydrogen. 



— 522, in the fifteenth line froni the top,/o>" in fault read at fault. 



