Chapter 2: Calculating Machines

The simplest form of calculating machine was the Abacus, on which the schoolboys of ancient Greece did their sums. It consisted of a smooth board with a narrow rim, on which were arranged rows of pebbles, bits of bone or ivory, or silver coins. By replacing these little counters by sand, strewn evenly all over its surface, the abacus was transformed into a slate for writing or geometrical lessons. The Romans took the abacus, along with many other spoils of conquest, from the Greeks and improved it, dividing it by means of cross-lines, and assigning a multiple value to each line with regard to its neighbours. From their method of using the calculi, or pebbles, we derive our English verb, to calculate.

During the Middle Ages the abacus still flourished, and it has left a further mark on our language by giving its name to the Court of Exchequer, in which was a table divided into chequered squares like this simple school appliance.

Step by step further improvements were made, most important among them being those of Napier of Merchiston, whose logarithms vex the heads of our youth, and save many an hour’s calculation to people who understand how to handle them. Sir Samuel Morland, Gunter, and Lamb invented other contrivances suitable for trigonometrical problems. Gersten and Pascal harnessed trains of wheels to their “ready-reckoners,” somewhat similar to the well-known cyclometer.

All these devices faded into insignificance when Mr. Charles Babbage came on the scene with his famous calculator, which is probably the most ingenious piece of mechanism ever devised by the human brain. To describe the “Difference Engine,” as it is called, would be impossible, so complicated is its character. Dr. Lardner, who had a wonderful command of language, and could explain details in a manner so lucid that his words could almost always be understood in the absence of diagrams, occupied twenty-five pages of the Edinburgh Review in the endeavour to describe its working, but gave several features up as a bad job. Another clever writer, Dr. Samuel Smiles, frankly shuns the task, and satisfies himself with the following brief description:--

“Some parts of the apparatus and modes of action are indeed extraordinary--and, perhaps, none more so than that for ensuring accuracy in the calculated results--the machine actually correcting itself, and rubbing itself back into accuracy, by the friction of the adjacent machinery! When an error is made the wheels become locked and refuse to proceed; thus the machine must go rightly or not at all--an arrangement as nearly resembling volition as anything that brass and steel are likely to accomplish.”[4]

Mr. Babbage, in 1822, entered upon the task of superintending the construction of a machine for calculating and printing mathematical and astronomical tables. He began by building a model, which produced forty-four figures per minute. The next year the Royal Society reported upon the invention, which appeared so promising that the Lords of the Treasury voted Mr. Babbage £1,500 to help him perfect his apparatus.

He looked about for a first-rate mechanician of high intelligence as well as of extreme manual skill. The man he wanted appeared in Mr. Joseph Clement, who had already made his name as the inventor of a drawing instrument, a self-acting lathe, a self-centring chuck, and fluted taps and dies. Mr. Clement soon produced special tools for shaping the various parts of the machine. So elaborate was the latter, that, according to Dr. Smiles, “the drawings for the calculating machinery alone--not to mention the printing machinery, which was almost equally elaborate--covered not less than four hundred square feet of surface!”

You will easily imagine, especially if you have ever had a special piece of apparatus made for you by a mechanic, that the bills mounted up at an alarming rate; so fast, indeed, that the Government began to ask, Why this great expense, and so little visible result? After seven years’ work the engineers’ account had reached £7,200, and Mr. Babbage had disbursed an additional £7,000 out of his own pocket. Mr. Clement quarrelled with his employer--possibly because he harboured suspicions that they were both off on a wild-goose chase--and withdrew, taking all his valuable tools with him. The Government soon followed his example, and poor Babbage was left with his half-finished invention, “a beautiful fragment of a great work.” It had been designed to calculate as far as twenty figures, but was completed only sufficiently to go to five figures. In 1862 it occupied a prominent place among the mechanical exhibits at the Great Exhibition.

[Illustration: A MECHANICAL CASHIER

The printing apparatus of a National Cash Register. It impresses on a paper strip the amount and nature of every money transaction; and also prints a date, number, advertisement, money value, and nature of business done on a ticket for the customer.]

We learn, with some satisfaction, that all this effort was not fated to be fruitless. Two scientists of Stockholm--Scheutz by name--were so impressed by Dr. Lardner’s account of this calculating machine that they carried Babbage’s scheme through, and after twenty years of hard work completed a machine which seemed to be almost capable of thinking. The English Government spent £1,200 on a copy, which at Somerset House entered upon the routine duty of working out annuity and other tables for the Registrar-General.

From Babbage’s wonderfully and fearfully made machine we pass to a calculator which to-day may be seen at work in hundreds of thousands of shops and offices.

It is the most modern substitute for the open till; and, by the aid of marvellous interior works, acts as account-keeper and general detective to the money transactions of the establishment in which it is employed.

There are very many types of Cash Register, and as it would be impossible to enumerate them all, we will pass at once to the most perfect type of all, known to the makers and vendors as “Number 95.”

This register has at the top an oblong window. Dotted about the surface confronting the operator are, in the particular machine under notice, fifty-seven keys; six bearing the letters A, B, D, E, H, K; three the words “Paid out,” “Charge,” “Received on Account”; and the others money values ranging from £9 to 1/4d.

These are arranged in vertical rows. At the left end of the instrument is a printing apparatus, kept locked by the proprietor; at the right end a handle and a small lever. Below the register are six drawers, each labelled with an initial.

A customer enters the shop, and buys goods to the value of 6s. 11d. An assistant, to whom belongs the letter H, receives a sovereign in payment. He goes to the register, and after making sure that his drawer is pushed in till it is locked, first presses down the key H, and then the keys labelled “6s.” and “11d.” Suddenly, like two Jacks-in-the-box, up fly into the window two tablets, with “6s. 11d.” on both their faces, so that customer and assistant can see the figures. Simultaneously a bell of a certain tone rings, drawer H flies open (so that he may place the money in it and give change, if necessary), and a rotating arm in the window shows the word “cash.”

The assistant now revolves the handle and presses the little lever. From a slot on the left side out flies a ticket, on the front of which is printed the date, a consecutive number, the assistant’s letter, and the amount of the sale. The back has also been covered with an advertisement of some kind. The ticket and change are handed over to the customer, the drawer is shut, and the transaction is at an end, except for an entry in the shop’s books of the article sold.

A carrier next comes in with a parcel on which five-pence must be paid for transport. Mr. A. receives the goods, goes to the register, presses his letter, the key with the words “paid out” on it, and the key carrying “5d.,” takes out the amount wanted, and gives it to the carrier.

Again, a gentleman enters, and asks for change for half a sovereign. Mr. B. obliges him, pressing down his letter, but no figures.

Fourthly, a debtor to the shop pays five shillings to meet an account that has been against him for some time. Mr. K. receives the money and plays with the keys K, “Received on account,” and “5s.,” giving a ticket receipt.

Lastly, a customer buys a pair of boots on credit. Mr. D. attends to him, and though no cash is handled, uses the register, pressing the letter “Charge,” and, say, “16s. 6d.”

Now what has been going on inside the machine all this time? Let us lift up the cover, take off the case of the printing apparatus, and see.

A strip of paper fed through the printing mechanism has on it five rows of figures, letters, etc., thus--

s. d.

H 6 11 Pd. A 0 5

B 0 0 Rc. K 5 0 Ch. D 16 6

The proprietor is, therefore, enabled to see at a glance (1) who served or attended to a customer, (2) what kind of business he did with him, (3) the monetary value of the transaction. At the end of the day each assistant sends in his separate account, which should tally exactly with the record of the machine.

Simultaneously with the strip printing, special counting apparatus has been (a) adding up the total of all money taken for goods, (b) recording the number of times the drawer has been opened for each purpose. Here, again, is a check upon the records.

This ingenious machine not only protects the proprietor against carelessness or dishonesty on the part of his employés, but also protects the latter against one another. If only one drawer and letter were used in common, it would be impossible to trace an error to the guilty party. The lettering system also serves to show which assistant does the most business.

Where a cash register of this type is employed every transaction must pass through its hands--or rather mechanism. It would be risky for an assistant not to use the machine, as eyes may be watching him. He cannot open his drawers without making a record; nor can he make a record without first closing the drawers; so that he must _give a reason_ for each use of the register. If he used somebody else’s letter, the ear of the rightful owner would at once be attracted by the note of his particular gong. When going away for lunch, or on business, a letter can be locked by means of a special key, which fits none of the other five locks.

The printing mechanism is particularly ingenious. Every morning the date is set by means of index-screws: and a consecutive numbering train is put back to zero. A third division accommodates a circular “electro” block for printing the advertisements, and a fourth division the figure wheels.

The turn given to the handle passes a length of the ticket strip through, a slot--prints the date, the number of the ticket, an advertisement on the back, the assistant’s letter, the nature of the business done, and feeds the paper on to the figures which give the finishing touch. A knife cuts off the ticket, and a special lever shoots it out of the slot.

The National Cash Register Company, for prudential reasons, do not wish the details of the internal machinery to be described; nor would it be an easy task even were the permission granted. So we must imagine the extreme intricacy of the levers and wheels which perform all the tasks enumerated, and turn aside to consider the origin and manufacture of the register, which are both of interest.

The origin of the cash register is rather nebulous, because twenty-five years ago several men were working on the same idea. It first appeared as a practical machine in the offices of John and James Ritty, who owned stores and coalmines at Dayton, Ohio. James Ritty helped and largely paid for the first experiments. He needed a mechanical cashier for his own business, and says that, while on an ocean steamer _en route_ to London the revolving machinery gave him the suggestion worked out, on his return to Dayton, in the first dial-machine. This gave way to the key-machine with its display tablet, or indicator, held up by a supporting bar moved back by knuckles on the vertical tablet rod.

[Illustration: FIG. 1]

The cut (Fig. 1) shows the right side of this key register, the action of which is thus described by the National Cash Register Company. The key A, when pressed with the finger at its ordinary position--marked 1--went down to the point marked 2. Being a lever and pivoted to its centre, pressing down a key elevated its extreme point B. This pushed up the tablet-rod C, having on its upper part the knuckle D. This knuckle D, pushed up, took the position at E; that is, the knuckle pushed back the supporting-bar F, and was pushed past it and held above it. If the same operation were performed on another key, the knuckle on its vertical rod, going up, would again push the supporting bar back, which would release the first knuckled rod, and leave the last one in its place. This knuckled rod had on its upper end the display tablet, or indicator G. James and John Ritty claimed and proved that they invented this, but the attorney for the Dayton Company (formed by them) in the Supreme Court was compelled to admit that this mechanism was old. Yet if machines built like this were exhibited elsewhere, they were at most only experimental models, and none of them had ever gone into practical or commercial use. In fact, at this time nothing had been really contributed which was useful to the public or used by the public.