T 



TO CORRESPONDENTS. 



We ai-e sorry tliat we cannot at present comply with the wish of our Corre- 

 spondent J. M. — We acknowledge the importance of the Essay respecting which he 

 writes to us; but we must endeavour to allot to each subject its due proportiorti 

 of our space. 



Tlie Letter from Professor Littrow to Baron Zach has been received; — 

 also a second Communication on Iron from Mr. D. Musiiet ; and a Letter froiri 

 . Mr. W. DoBBiE. 



We hope to be favoured with an account of a Series of Experiments on the 

 Expansion, &c. of Vapours, which will be very desirable during the present dis- 

 cussion of the subject. 



Published by the Authority and at the Expense of the Board of 

 Longitude. 8vo. Price 10s. 



ABLES to be used with the NAUTICAL ALMANAC, for 

 finding the LATITUDE and LONGITUDE at SEA. 



By the Rev. W. LAX, M.A. F.R.S. 

 Lowndes' Professor of Astronomy and Geometry in the University of 



Cambridge. 

 Containing a complete and compendrous Set of Tables, in which the 

 quantities are taken out by immediate inspection, and the proportional 

 parts are additive ; with easy and accurate methods of solving the various 

 Problems required, and the newest determinations of the Latitudes aftd 

 Longitudes of places: intended as a Substitute for the Requisite Tables. 



Sold by John Murray, Publisher to the Board of Longitude, Albemarle- 

 street. 



Published by the Authority and at the Expense of the Board of 

 Longitude. 4to. Pri;e 31. 



TABLESof LOGARITHMS of all NUMBERS, from 1 to lOlOOO, 

 and of the SINES andTANGENTS to every SECOND of the 

 QUADRANT. 



By MICHAEL TAYLOR, 

 Author of the Sexagesimal Tables. 



With a Preface, and Precepts for the Explanation and Use of the 8am», 



By NEVIL MASKELYNE, F.R.S. Astronomer Royal. 



Sold by John Murray, Publisher to the Board of Longitud«, Albe- 

 marle-street. 



ENGRAVINGS. 



Vol. LIV. A Plate illustrative of the Menai Bridge. — A Plate illus- 

 trative of Mr. Lowe's Description of a Mercurial Pendulum.— A Plate 

 illustrative of Mr. Hare's Calorimotor, a new Galvanic Instrument. — A 

 Plate illustrative of Captain Sabine's Paper on Irregularities observed in 

 the Direction of the Compass Needles of the Isabella and Alexander in 

 the late Voyage of Discovery ; and Mr. Scoresby's Anomaly in the Va- 

 riation of the Magnetic Needle as observed on Ship-board. ' . 



