On Mr. *Babbage's* new machine for calculating and printing mathematical and astronomical tables.

From *F. Baily*.

London 1823. Nov 28.

This invention of M^{r.} *Babbage's* is one of the most curious and important in modern times; whether we regard the ingenuity and skill displayed in the arrangement of the parts, or the great utility and importance of the results. Its probable effect on those particular branches of science which it is most adapted to promote, can only be compared with those rapid improvements in the arts which have followed the introduction of the steam engine: and which are too notorious to be here mentioned.

The object which M^{r.} *Babbage* has in view, in constructing his machine, is the formation and printing of mathematical tables of all kinds, totally free from error in each individual copy: and, from what I have seen of the mechanism of the instrument, I have not the least doubt but that his efforts will be crowned with success. It would be impossible to give you a correct idea of the form and arrangement of his machine, or of its mode of operation, without the help of various plates, and a more minute description than is consistent with the nature of your journal. But, it will be sufficient to say that it is extremely simple in its construction, and performs all its operations with the assistance of a very triffling mechanical power. Its plan may be divided into two parts, the mechanical and the mathematical.

The mechanical part has already been attained by the actual construction of a machine of this kind: a machine for computing numbers with two orders of differences only, but which I have seen perform all that it was intended to do, not only with perfect accuracy but also with much greater expedition that I could myself perform the same operations with the pen. From the simplicity of the mechanism employed, the same principles may be applied in forming a much larger machine for computing tables depending on any order of differences, without any probability of failure from the multitude of wheels employed. The liberality of our government (always disposed to encourage works of true science and real merit) has induced and enabled Mr. *Babbage* to construct a machine of this kind, capable of computing members with four orders of differences; and which will shortly be completed. To this machine will be attached an apparatus that shall receive, on a soft substance, the impression of the figures computed by the machine: which may be afterwards stereotyped or subjected to some other processes, in order to ensure their permanency. By this means, each individual impression will be perfect.

The mathematical part depends on the method of differences to which I have above alluded: a principle well known to be, at once, simple and correct in its nature, and of very extensive use in the formation of tables, from the almost unlimited variety of its applications. It has been already successfully applied in the computation of the large tables of logarithms in France; and is equally applicable in the construction not only of astronomical tables of every kind, but likewise of most of the mathematical tables now in use.—

But, the full and complete application of this, and indeed of every other principle in the formation of tables, has been hitherto very much impeded by the impossibility of confining the attention of the computers to the dull and tedious repetition of many thousand consecutive additions and subtractions, or other adequate numerical operations. The substitution however of the unvarying action of machinery for this laborious yet uncertain operation of the mind, confers an extent of practical power and utility on the method of differences, unrivalled by any thing which it has hitherto produced: and which will in various ways tend to the promotion of science.

The great object of all tables is to save time and labour, and to prevent the occurrence of error in various

29