i CONTENTS. 



XII. Researches on the Structure of the Scales of Fii*he8. 

 By Dr 1.. Mandl. With an illustrative Plate. 

 Continued from page 126 of this volume, . 274 



XIII. Remarks occasioned by Dr Mandl's Observations on 



the Structure of the Scales of Fishes. By M. 

 Agassiz, .... 287 



XIV. On the best Means of Burning Gas for supplying Heat. 



By Sir John Robison, K.H., Sec. R.S.E., M.S.A., 291 

 XV. On the best Method of Burning Gas for the purpose 

 of Illumination. By Sir John Robison, K. H., 

 Sec. R.S.E., M.S.A., ... 293 



XVI. Abridgment of an Essay on the Construction of Ob- 

 lique Arches. By Edward Sang, M.S.A., Civil 

 Engineer, Edinburgh. Communicated by the So- 

 ciety of Useful Arts for Scotland, . 301 

 XVII. Lord Gray's Meteorological Table for 1839, 319 

 XVIII. Mean Results, during each Month for Seven Years, 

 of a Register of the Thermometer, kept at Alford, 

 Aberdeenshire; about Lat. 57° 13' N. ; 420 feet 

 above the Sea, and 26 miles inland from the Coast 

 at Aberdeen. Also, the Extremes of both Heat and 

 Cold in each Month, the Mean of each Year, the 

 Mean from April to September both inclusive, and 

 from July to September both inclusive, and the 

 quantity of Rain that fell in the five last Years, with 

 the Fair and Rainy Days. By the Rev. James 

 Fakquharson, LL.D., F.R.S., . . 320 



XIX. Register of the Weather, kept at Canaan Cottage, 

 Edinburgh, for 1839. By Alexander A die, Esq., 

 F.R.S.E., M.W.S., S:c., . . .322 



XX. Summary of Observations of the Barometer, Thermo- 

 meter, &c. for 1839, kept at the Manse of Abbey 

 St Bathan's, Berwickshire, Lat. 55° 52', W. Long. 

 2," 23', at the height of about 450 feet above the 

 level of the Sea. By the Rev. J. Wallace, A.M. 

 &c., . . . . .323 



XXI. Abstract of Meteorological Observations for 1839, 

 made at Applegarth Manse, Dumfriesshire. By the 

 Rev. W. Dunbar, . . . 324 



XXII. Results of a Rain-Gauge kept at Carlisle. Commu- 

 nicated by Mr Joseph Atkinson, . . 326 



