166 



Mr. W. S. Jcvons on the Mechanical 



[Jan. 20, 



Transactions {continued). 



1868, par S. A. Sexe. 4to. Christiania 18G9. Anatomisk Bcskri- 

 velse af Bursa) Mucosae, af A. 8. D. Synncstvedt. 4to. Christiania 

 I860. The University. 



Norske Afeteorologiske Institut. Norsk Meteorologist: Aarbog for 

 1868, 2 den Aargang. 4to. Christiania 1869. The Institute. 



Coimbra : — Eniversidadc. Annuario 1869-70. 12mo. Coimbra 1869. 



The University. 



Dublin : — Eoyal Dublin Society. Journal. No. 37. 8vo. Dublin 1868. 



The Society. 



Eoyal Geological Society of Ireland. Journal. Vol. II. Part 1. 8vo. 

 Dublin 1868. The Society. 



Edinburgh : — Eoyal Scottish Society of Arts. Transactions. Yol. VIII. 



Part 1. 8vo. Edinburgh 1869. The Society. 



Emden : — Naturforschende Gesellschaft. Jahresberichte 1858-68, 

 44-54. 8vo. Emden 1859-69. The Society. 



Haarlem : — Societe Hollandaise des Sciences. Archives Neerlandaises 

 clcs Sciences Exactes et Naturelles. Tome IV. 8vo. La Haye 1869. 



The Society. 



London : — Eoyal Asiatic Society. Journal. New series. Vol. IV. Part 1. 



8vo. London 1869. The Society. 



Throndhjem : — Kongelige Norske Videnskabers Selskabs-Skrifter i det 



19de Aarhundrede. Bind V. Heft 2. 8vo. Throndhjem 1865-68. 



The Society. 



Vienna: — ILK.Sternwarte. Annalen, von C. von Littrow. Dritter Eolgc. 

 Band XV. Jahrgang 1865. 8vo. Wien 1869. The Observatory. 



Galton (Douglas, E.E.S.) An Address on the general principles which 

 should be observed in the Construction of Hospitals. 8vo. London 1869. 



The Author. 



Palombo (E.) Delia Proprieta e degli Ordinamenti Sociali, studi storico- 

 economici. 8vo. Napoli 1869. The Author. 



Townsend (E,, E.E.S.) On the Nodal Cones of Quadrinodal Cubics, and 

 the Zomal Conies of Tetrazomal Quartics. 8vo. London 1869. 



The Author. 



The following communications were read : — 



I. " On the Mechanical Performance of Logical Inference." By 

 W. Stanley Jevoxs, M.A. (Lond.), Professor of Logic &c. 

 in Owens College. Communicated by Professor E. Eoscoe. 

 Eeceived October 16, 1869. 



(Abstract.) 



It is remarkable that from the earliest times mechanical assistance has 

 been employed in mathematical computation. The use of pebbles, of the 



