a Knowledge of the Stars. 377 



Problem 5. To find the hour of the day by the sun. 



Turn the segment K, and elevate the index M, till the sun 

 is seen or shines through the sights O, P, and the scale L will 

 point to the hour and minute on the circle E F G. 



Problem 6. To find the hour of the night by means of a 

 star. 



Direct the index M to the star, so as to be seen through 

 the sights P, O ; then laying hold of the scale L, to keep it in 

 that position, turn the cone till the star on the projection is cut 

 by the scale, when the day of the month on the circle at the 

 bottom of the cone will coincide with the hour and minute 

 on the circle E F G. 



This instrument, though not capable of extreme accuracy, 

 might, by means of careful workmanship, and the addition of a 

 small telescope, be made sufficiently so for finding stars in the 

 day time ; but such a one as that now described will answer 

 all the purposes of a learner, and enable very young people to 

 acquire a correct and extensive knowledge of the stars in a 

 very short time. 



The surface of a cone has been adopted for the projection, 

 in preference to that of a globe or planisphere, having been 

 found, after repeated trials, the figure best suited to the nature 

 of the instrument. 



^.'tiri?>i't : . ., 



mm'-, 



An Introduction to the Comparative Aiiatomy of Ani7nals^ 

 compiled with constant reference to Physiology^ and elu- 

 cidated by twenty copper -plates. By C. J. Cams, M.D., 

 &c. Translated from the German, by R. T. Gore, Mem- 

 ber of the Royal College of Surgeons in London. 



Ip we except Sir Everard Home's splendid work on compa- 

 rative anatomy, we have no original treatise on that subject 

 which deserves notice ; and even Sir Everard's lectures must 

 rather be considered as a series of essays on detached parts 

 of that branch of science, than as a regular and systematic 

 view of it. We have long been acquainted with the w^ork of 

 Dr. Cams, and have always considered it as a laborious and 

 accurate epitome of the principal facts and authorities in 

 the study to which it relates. From the immense field of 

 inquiry which it embraces, it is necessarily complicated, and 



