Oe ne eae 
Miscellaneous Bibliography. 75 
with the preface to the Transactions of the Analytical Society, a 
small club established by Babbage, Herschel, Peacock, and several 
other students at Cambridge, to promote, as it was humorously 
expressed, the principles of pure D-ism, that is, of the Leibnitzian 
notation and the methods of French mathematicians. Until 1822 
Mr. Babbage’s writings consisted exclusively of memoirs u 
position, but because they display the deepest insight into the 
rinciples of symbolic methods. His memoir in the “ Cambridge 
hilosophical Transactions” for 1826, “On the Influence of Signs 
pe 
uman mind, 
As early as 1812 or 1813 he entertained the notion of calculating 
mathematical tables by mechanical means, and in 1819 or 1820 
began to reduce his ideas to practice. Between 1820 and 1822 he 
completed a small model, and in 1823 commenced a more perfect 
metallic wheels and levers. It was to be capable of any analytical 
Operation, for instance, solving equations and tabulating the most 
re isla formule. Nothing but a careful study of the pub- 
is ; i 
abbage asserted to be possible would have been theoretically 
possible. The engine was to possess a kind of power of prevision, 
and was to be so constructed that intentional disturbance of 
the loose parts would give no error in the final result. : 
Although for many years Mr. Babbage entertained the intention 
