126 Proceedings of the Royal Society 
Monthly Eeturn of Births, Deaths, and Marriages Registered in the 
eight Principal Towns of Scotland, January 1867. 8vo. — 
From the Registrar-General. 
Quarterly Return of Births, Deaths, and Marriages Registered in 
the Divisions, Counties, and Districts of Scotland. No. 48. 
8 vo. — From the Registrar -General. 
American Journal of Science and Arts. Second Series. No. 127, 
New Haven, 1867. 8vo. — From the Editors. 
Notes on the G-reat Ganges Canal. By T. Login, Esq., C.E. 
Roorkee, 1867. 8vo. — From the Author. 
Roads, Railways, and Canals for India. By T. Login, Esq., C.E. 
Roorkee, 1866. 8vo. — From the Author. 
Historical Sketch and Laws of the Royal College of Physicians of 
Edinburgh, from its Institution to December 1865. Edin- 
burgh, 1867. 4to. — From the College. 
Bulletin de l’Academie Royale des Sciences, des Lettres et des 
Beaux-Arts de Belgique. Tome XXIII. No. 2. Bruxelles, 
1867. 8 vo. — From the Academy. 
Monatsbericht der Koniglich Preussischen Akademie der Wissens- 
chaften zu Berlin, November 1866. Berlin, 1867. 8vo.— 
From the Academy. 
Sveriges Geologiska Undersokning, pa ofifentlig bekostnad utford 
under ledning af A. Erdmann. Liv. 17-21 (with maps). 
Stockholm, 1866. — From the Geological Commission of Sweden. 
Nova Acta Regiae Societatis Scientiarum Upsaliensis. Yol. VI. 
Fascs. 1. Upsala, 1866. 4to. — From the Society. 
Monday , ls£ April 1867. 
Sir DAVID BREWSTER, President, in the Chair. 
The following Communications were read : — 
1. On the Analysis of Compound Ethers. By W. Dittmar. 
In many cases the best guarantee of the purity of a chemical 
substance is the method by which it has been prepared. If the 
processes are well devised and carefully conducted, they constitute 
