ON BABBAGE’S ANALYTICAL ENGINE. 701 
ing more complicated, will in many respects be of simpler construc- 
tion; and it is a remarkable circumstance attending it, that with very 
simplified means it is so much more powerful. 
The article in the ‘ Edinburgh Review’ was written some time pre- 
ious to the occurrence of any ideas such as afterwards led to the in- 
yention of the Analytical Engine; and in the nature of the Difference 
Engine there is much less that would invite a writer to take exclu- 
sively, or even prominently, the mathematical view of it, than in that 
of the Analytical Engine ; although mechanism has undoubtedly gone 
much further to meet mathematics, in the case of this engine, than 
of the former one. Some publication embracing the mechanical view 
_ of the Analytical Engine is a desideratum which we trust will be sup- 
plied before long. 
Those who may have the patience to study a moderate quantity 
of rather dry details, will find ample compensation, after perusing the 
article of 1834, in the clearness with which a succinct view will have 
and generalized memoir. The very difference in the style and object 
of these two articles, makes them peculiarly valuable to each other ; at 
| least for the purposes of those who really desire something more than 
a merely superficial and popular comprehension of the subject of cal- 
culating engines. A.A. L. 
Notre B.—Page 676. 
__ That portion of the Anaiytical Engine here alluded to is called the 
orehouse, It contains an indefinite number of the columns of dises 
| described by M. Menabrea. The reader may picture to himself a pile 
of rather large draughtsmen heaped perpendicularly one above another 
to a considerable height, each counter having the digits from 0 to 9 
nseribed on its edge at equal intervals; and if he then conceives that 
the counters do not actually lie one upon another so as to be in contact, 
which passes perpendicularly through their centres, and around which 
each dise can revolve horizontally so that any required digit amongst 
those inscribed on its margin can be brought into view, he will have a 
good idea of one of these columns. The lowest of the dises on any 
plumn belongs to the units, the next above to the tens, the next above 
his to the hundreds, and so on. Thus, if we wished to inseribe 1345 
n a column of the engine, it would stand thus ;— 
OS Oo 
sd e Difference Engine there are seven of these columns placed 
side by side in a row, and the working mechanism extends behind them ; 
the general form of the whole mass of machinery is that of a quadran- 
ilar prism (more or less approaching to the cube) ; the results always 
appearing on that perpendicular face of the engine which contains the 
olumns of dises, opposite to which face a spectator may place himself. 
| In the Analytical Engine there would be many more of these columns, 
| probably at least two hundred. The precise form and arrangement 
