At the end of September will be published by the undersigned, 



ASTRONOMISCHE UNDULATIONSTHEORIE, 



oder die 



Lehre von der ABERRATION DES LICHTES, 



von 



Dr. E. KETTELER, 



Professor an der Universitat Bonn. 

 With 44 Wood Engravings printed in the text. 18 sheets. Price 2 Thalers. 

 September 1, 1873. Bonn : P - Neusser. 



NEW EDITION OF MITCHELL'S ASSAYING. 



Just published, in 8vo, with 199 Woodcuts, price 31s. 6d. 



A MANUAL OF PRACTICAL ASSAYING. 



By JOHN MITCHELL, F.C.S. 



Fourth edition, in which are incorporated all the recent valuable improvements 

 in Assaying made in this country and abroad ; including Volumetric and Colori- 

 metric Assays, and the Blowpipe Assays. 



Edited and for the most part rewritten by 

 WILLIAM CROOKES, F.R.S. &e. 

 " The work, as it now stands, may safely be taken as a guide by buyers of ores, 

 and by all persons engaged in the industry of chemical manufacture ." — Mining 

 Journal. 



London : Longmans, Green, and Co., Paternoster Row. 



Just published, in 4to, on fine paper, with Six Plates, price 3s. 6d., 



Part XII. of 



RELKtULE AQUITANICJE; 



Being Contributions to the Archaeology and Palaeontology of Perigord and the 



adjoining Provinces of Southern France. 



By EDOUARD LARTET and HENRY CHRISTY. 



Edited by T. RUPERT JONES, F.R.S., F.G.S., &c, 

 Professor of Geology, Royal Military and Staff Colleges, Sandhurst. 

 This Work will be illustrated with numerous well-executed Lithographic Plates 

 of the Weapons, Tools, and Ornamental Work, in Stone, Bone, and Horn, of the 

 Prehistoric Cave-dwellers of Perigord ; also of the Osseous Remains of the Con- 

 temporaneous Animals. 



To be completed in about 15 Parts (price 3s. 6d. each). 



Williams and Norgate, 14 Henrietta Street, Covent Garden, London, and 

 20 South Frederick Street, Edinburgh ; J. B. Bailliere & Fils, Paris. 



Now ready, with Engravings, 8vo, 12s.. 



AN INTRODUCTION TO PHYSICAL MEASUREMENTS, 

 With 

 APPENDICES ON ABSOLUTE ELECTRICAL MEASUREMENT, etc. 

 By Dr. F. KOHLRAUSCH, 



Professor at the Grand Ducal Polytechnic School at Darmstadt. 



Translated from the Second German Edition by T. H. WALLER, B. A., B.Sc, 



and H. R. PROCTER, F.C.S. 



J.and A. Churchill, New Burlington Street. 



Now readv, with 48 Wood Engravings, foolscap 8vo, 5s., 



NOTES ON NATURAL PHILOSOPHY. 



By G. F. ROD WELL, F.R.A.S., 



Science Master in Marlborough College, late Lecturer on Natural Philosophy in 



Guy's Hospital. 

 " There cannot be a doubt that this little book will be of use to science teachers 

 and science students.' — Nature. 



J. & A. Churchill, New Burlington Street. 



[ADVERTISEMENTS continued on 3rd page of Cover. 



