# Typographical Errors and Hints

The *Sketch of the Analytical Enigine.. * uses some typgraphical conventions not common today, and there are a few apparent typographical errors.

It is available as a facsimile unter archive.org (processed version removing the background: menabrea_lovelace1843_analyticalengine.pdf) and has been typeset anew in several places, e.g. in *Charles Babbage and his CALCULATING ENGINES*, edited by Philip and Emily Morrison, Dover Publications 1961, *The Works of Charles Babbage*, edited by Martin Campbell-Kelly, Vol. 3, London 1989, and online at http://fourmilab.ch/babbage/sketch.html. Follows a list of typographic errors which are not generally all corrected (pagenumbers refer to the original publication):

- The well-discussed case of the cos on p. 637, where the phrase
*when the cos of n=∝ has been foreseen …*should clearly read*the case of …* - In the first equations of
*Note E*(p.712), most reprints correctly use the upper index '1' instead of the prime as in the original; the equations referred to are not on p.679, but on p. 684 - Also in
*Note E*p.714, equation 3, there is missing a*cos*in the second term of the right hand side; the formula should read (see page 723):

`cos n theta * cos theta = 1/2 cos [(n+1) theta] + 1/2 cos [(n-1) theta]`

- In the final table ending
*Note G*, in operation 4, the operands have to be exchanged: V_{4}has to be divided by V_{5} - In the same table in line 21, it must read
^{2}V_{12}instead of^{0}V_{12}in the result column ~~In the same line, the zero in column V~~_{11}must be dropped. If the loop is repeated, the value is needed in the next round.- In the same line 21, in the 5th column (
*Indication…*) the second line^{0}V_{12}=^{2}V_{12}is exceptional, as elsewhere in this column only*Variables acted upon*from the 3rd column are used; systematically, it would be `^{0}V_{11}=^{5}V_{11}. - In operation 24, the negative value of V
_{13}has to be transferred to V_{24}, i.e. V_{24}-V_{13}must be calculated, and in the 6^{th}column read =-B_{7} - Also in the same line, in the (forth to last) column for V
_{13}the digit zero must printed, as is given in the 5^{th}column, according to the rule that intermediate variables have to be to set to zero finally. - The last signature (p.731) is not
*A.A.L.*, but*A.L.L.*, which is most probably only a typeset error.

Note that in line 25 in the result column and in the next one right to the equals sign should read ^{2}V_{3} instead of ^{1}V_{3}; however AAL argued that the upper index is correct, as this value is for the next round of calculations, and thus must have the upper index 1 for a starting value.

Note also that instead of nested parenthesis, parts of equations are overbarred, e.g. (4.) on page 716.

Martin Campbell-Kelley's edition corrects all, but not the wrong division in operation 4 of the table for the calculation of Bernoulli's numbers, although having used a simulation as well as Petrenko, refering to Tee's review, as of the footnote on p.159. Probably both corrected the error during testing, and missed a note on this.