406 Scientific Intelligence. — New Publications^. 



table. We approve more of the table of proportional logarithms 

 to twenty-four hours by Lax and others, which gives the answer 

 at one inspection. 



Tables XIII. gives the correction to be added to the sun's al- 

 titude, and combines the dip, refraction, parallax and semi-dia- 

 meter. We confess, however, we prefer that these corrections 

 sliould not be slumped together in this way, and have always 

 made it a rule to teach our young friends to shun such tables, 

 and take out each correction separately. 



Table XVI. has been re-computed, expressly for this work, 

 from the sun's horizontal parallex taken at S.'^CS. 



Table XVII. gives Mr Ivory's refractions, but it has been 

 considerably extended, and, as we think, improved, by having 

 the refractions and their logarithms to every KY from the zenith 

 to the horizon. 



Tlie addition of proportional parts to the three succeeding ta- 

 bles for the corrections due to the thermometer and barometer 

 is very praiseworthy, as it materially facilitates their applica- 

 tion. 



We observe, that a column has been added to table XXVII. 

 of Equations for second differences, by which they are adapted 

 to the sun's declination ; and although, in ordinary cases, no cor- 

 rection for the irregularity of the sun's motion is necessary, it 

 does become of consequence in very accurate observations for 

 latitude made near the Solstices. 



Table LIX. gives the logarithms of the numbers in Rossel's 

 well known table for correcting the longitudes determined by 

 chronometer, when the rate has been found to have varied. 

 Everything v/hich contributes to the accuracy of such determi- 

 nations is valuable ; and we think Mr Galbraith, by dwelling 

 so frequently on these minute corrections, does essential service 

 to science, by making observers aware how easily and safely they 

 may be taken into account. 



Table LXIII. contains, in a compendious shape, many ex- 

 tremely useful numbers, with their logarithms and comple- 

 ments. 



Tables LXVI. and LXVII , for the third and fourth diffe- 

 rences of the moon's motion, are by Mr Henderson, a very in- 

 genious mathematician in Edinburgh. 



