404 Scientific InteUigeiice. — Nexo Publications, 



3. ^Alathematical and Astronomical Tables for the nse of Stu- 

 dents of Mathematics, Practical Astronomers, Siirveijo7'Sy 

 Engineers, and Navigators. By William Galbraith, 

 M. A. Oliver & Boyd. Edinburgh. 9s. 

 This portable and cheap volume is well worthy of the attention 

 of the practical men alluded to in the title page, and we have no 

 doubt, that, when its merits come to be sufficiently known, it will 

 supersede the use of every other with which we are acquainted. 

 It is needless to mention, that Mr Galbraith g'rves all the ordinary 

 tables to be found in works with similar objects, such as the lo- 

 garithms of numbers, logarithmic sines and tangents, and others, 

 without which no surveyor, seaman, or astronomer, can advance 

 a step ; and we shall confine ourselves in this notice to an enu- 

 meration of such additions and improvements as Mr Galbraith 

 has made, and which we think claim for his work, as we have 

 said above, the notice of all men who are really at work on such 

 subjects. 



In the first place, we consider that Mr Galbraith has great 

 merit for giving, in a clear, well ordered, and perfectly scienti- 

 fic style, such a course of demonstrative reasoning on the theory 

 as well as the practice of his subject, as cannot fail to be very 

 useful to students who have a real wish to understand what they 

 are about, and whose better taste and judgment have hereto- 

 fore been offended by these epitomes which, to use their slang, 

 phrase, have been reduced to the lowest capacity. The various 

 methods of obtaining the longitude, are discussed at some length, 

 and with singular clearness. We are not aware that in any other 

 work of this elementary nature, those minute corrections in the 

 lunar method are given ; and, in fact, we suspect few navigators 

 are aware of their importance. We allude to the equations for 

 second differences in the distances, which are correctly given only 

 for every 3 hours in the Nautical Almanac, but which are not 

 found in strictness, for an intermediate period, by simple arithme- 

 tical proportion. This equation, in some cases^ amounts to 6 se- 

 conds of distance, 12 seconds of time, or 3 minutes of longitude. 

 Mr Galbraith has computed two little tables for obtaining the pro- 

 per correction (Introduction, page 102.) Another small correc- 

 tion on account of the oblique semidiameter, is found in two tables 

 by Dr Young, given at page 101. And a table is given by Mr 



