PREFACE. 



At this period, when science is so generally cultivated, it can scarcely be 

 necessary to enter into a minute detail of the various instances in which the 

 Royal Society of London has contributed to the advancement of natural 

 and experimental knowledge, by the publication of its Memoirs, under the 

 title of Philosophical Transactions. These volumes consist of an invaluable 

 collection of observations and discoveries made by the most eminent philoso- 

 phers of the seventeenth and eighteenth centuries ; among whom may be 

 mentioned a Boyle, a Newton, a Halley, and a Hales ; to say nothing of 

 other celebrated philosophers, who have contributed to this Collection in 

 later days and in our own time. 



It cannot then excite surprise that a work, enriched by communications 

 from men so distinguished in the different departments of science, and which, 

 from the variety of topics it embraces, may be consulted with equal advantage 

 by the astronomer, the geometrician, the natural historian, the anatomist, 

 the physiologist, and the chemist, — should be held in the highest estimation, 

 not only in this country, but in every enlightened part of the globe. Indeed 

 the Transactions of the Royal Society of London are justly regarded as a 

 lasting and most honourable testimony to the genius and philosophical spirit 

 of the British nation. No scientific library is complete without them. 



Every person, therefore, who entertains the least ardour for philosophical 

 pursuits, cannot but be desirous of possessing so valuable a work. But, at 

 the present period, few can satisfy their wishes in this respect, in conse- 

 quence of the high price and extreme scarcity of the Original Collection ; a 



