## William Thomson

If you can not measure it, you can not improve it.
Lord Kelvin

At the present time, predictions of tides and tidal currents are generated by computer. The prediction of the periodic tides is the oldest form of oceanic prediction. How were such predictions made before the electronic age?

Ancient civilizations recognized the relationship between the rise and set of the Moon and the rise and fall of the tides. Initially, tide predictions used rule-of-thumb to relate the times of the tides to the rise and set of the Moon. Such techniques indicate that the high tide would occur a certain number of hours after the Moon had passed overhead, or that the low tide had occurred a certain number of hours after the Moon rose or set. However, such methods provide general information which may not be accurate. A more precise, harmonic method of predicting tides was developed in the mid-1800s.

The first scientist to explain how tides are generated by the gravitational forces of the moon and sun was Isaac Newton (in the 1690s). In 1775 Pierre Laplace suggested, that tides should be represented as a series of harmonic oscillations. However, it was the British mathematician, physicist, and engineer William Thomson (later known as Lord Kelvin) who announced, in 1867, that he had developed a method for harmonic analysis and prediction.

The harmonic method of predicting tides is based on the fact that tides are the result of the gravitational forces of the Moon and Sun. The magnitude of these forces is due to the changing positions of the Earth, Moon, and Sun relative to each other. As the gravitational forces change, so do tides. The orbits of the Earth, Moon, and Sun are in constant motion, following repeating patterns of different frequencies that can be observed, analyzed, and predicted.

Some of these are orbiting patterns we are familiar with—the daily rotation of the Earth relative to the Sun (24 hours—a solar day); the rotation of the Earth relative to the Moon (24 hours and 50 minutes—a sidereal day); the orbit of the Moon around the Earth (29.5 days—the changing phases of the Moon); the orbit of the Earth around the Sun (365.25 days—a calendar year). There are many more—some with periods of a few hours, others with periods of months—which are harder to describe and visualize.

Using the timing of these different and periodic changes in the positions of the Earth, Moon, and Sun, scientists analyzed tide observations for changes that occur with the same frequencies. They were able to connect changes in the tides to specific changes in the positions of the Earth, Sun, and Moon, representing them as several sine curves, each with a frequency matching the frequency of one of the periodic motions of the Earth, Sun, and Moon, and with an amplitude equalling the contribution of a particular motion to the tides at a given location.

These “connections” are called “tidal harmonic constituents.” By combining the effect of all the constituents for a location, i.e., by adding and subtracting the various sine curves, the tides at that location can be predicted—for the present but also for dates in the future or in the past to assist in an analysis of past or future events. More than 200 tidal harmonic constituents have been mathematically defined. However, for most locations, many of these constituents have no real effect on the tides and can thus be safely discounted.

Manually adding and subtracting the effects of multiple sine curves is a daunting task. William Thomson made use of the very regular nature of the harmonic constituents to automate tide predictions.

Sine curves have a very well-defined period and amplitude, thus the effects could be mechanically reproduced using a gear, attached pin, and pulley. This developed into a machine made up of dozens of gears and pulleys, each gear designed to have the same period as one of the tidal harmonic constituents. The pin made it possible to set the amplitude of the constituent, while a chain ran over a pulley with a pen attached to it. The gears and pins pulled on the pulley and chain, thus moving the pen and tracing a curve on a roll paper—a curve which was the resulting tide prediction.

The machines built to predict the tides were finely crafted of brass and iron. The first such machine, a kind of analog computer, was built in London (1872) and calculated the tides using 10 harmonic constituents. This machine, designed by Thomson with the collaboration of Edward Roberts (1845-1933, assistant at the Nautical Almanac Office), and craftsman Alexander Légé, who constructed it, used a pen and paper trace to record the predicted tides. Thomson’s older brother, James, a professor of civil engineering at Queen’s College Belfast, designed the disk-globe-and-cylinder integrator that was used for the tidal harmonic analyzer.

In the machine, each of the 10 components was associated with a specific tidal constituent and had its own gearing to set the amplitude. The components were geared together so that their periods were proportional to the periods of the tidal constituents. A single crank turned all of the gears simultaneously, having the effect of summing each of the cosine curves. As the user turned the crank, an ink pen traced the resulting complex curve on a moving roll of paper. The device marked each hour with a small horizontal mark, making a deeper notch each day at noon. Turning the wheel rapidly allowed the user to run a year’s worth of tide readings in about 4 hours.

## Daniel Alroy

Awareness only knows now; the mind imagines time.
Rupert Spira

In the late 1960s and early 1970s, Daniel Alroy, a round‐faced man with thinning, sandy hair from New York, was responsible for steering Philips, Appel & Walden Co., a successful underwriter of high‐technology stocks, into the fastest growing segment of the computer industry and has proved a good judge of fashions and fads in the past. In the spring of 1972, deeply concerned about the future of the mini‐computer companies, Alroy got into a fight with Intel. He had set out to prove a point that a cheaper simpler computer can be made. Alroy succeeded and his Q1 Corp. became the first company to develop a complete, standalone, microcomputer system, integrated with a screen, keyboard and floppy drives. It was first delivered on 11 December 1972, based on the Intel 8008 processor that was introduced on the market only eight months earlier, in April 1972.

Alroy wanted to build a system with a wider scope of applicability, than existing at the time, so he designed a general-purpose computer, which would:
* Replace a multiplicity of limited-purpose systems
* Perform the functions with greater specificity
* Accomplish both above goals at a lower cost

The first Q1 computer from 1972 was a typewriter design with alphanumerical keyboard (see the nearby image), a single-line 80-character display, 16KB memory (expandable to 64 KB), floppy drives (8″ diskette, a recording medium as used in IBM 3740), and build-in printer. It was very impressive, and aimed to all from accounting to word-processing machines, to scientific calculators. The Q1 system software included: PL/1 high-level programming language and MACRO assembler (programming tools), Disk Operating System (command interpreter), Editor (ASCII-files processing), Trace Routine (a debugging tool), Sort Routine, Print Routine, Disk Dump, Join Routine, and Function Library.

In 1973, Alroy met Heinz Nixdorf, the president of Nixdorf Computer Company of Paderborn, Germany. Following that meeting, Q1 Corporation received ten monthly payments of \$40,000 from Nixdorf Computer in exchange for a sale of know-how. The income from the know-how sale expedited the development of the 8080-based Q1 microcomputer system, named Q1/Lite. In April 1974, Intel introduced a second-generation 8-bit microprocessor, the 8080. That month, Q1 shipped a pre-production unit of its 8080-based microcomputer system, on loan and with a buy option, to the Israeli Air Force. In June 1974, Q1 received a follow-up order for a number of 8080-based systems, which were subject to acceptance tests. The first two 8080-based systems were delivered in August 1974, and the pre-production unit was returned to Q1.

The Q1/Lite was an improved multi-purpose system (see Q1 Sales Brochure), which can be used as a terminal for mainframe computers, for data entry, engineering, word processing, etc. In 1974, Computer Science Corporation made a study of microcomputer systems for NASA. Based on the recommendation, the Q1/Lite computer systems were installed in all eleven NASA bases. Later Q1 Co. put into production third generation of the Q1 system, which used the Z80 processor, and fourth generation, using a 68000 CPU.

In 1979, the National Enterprise Board, an entity of the British Government, invested \$11.5 million in a joint venture with Q1 Corporation. Alroy used the opportune moment to install a president in his place, and in 1981 resigned and returned to his interest in the relation of mind and brain. He even wrote a book with his thoughts, The New Foundation of Knowledge.

Source: The Advent of the Microcomputer Era: An Eyewitness Account, © 2017 Daniel Alroy.

## Alois Salcher

A lazy man is the devil’s handyman.
Austrian proverb

At the beginning of the 20th century, the Austrian engineer and businessman from Innsbruck Alois Salcher devised and put into production a very interesting calculating machine. Despite its original construction, the machine was never much of a success, and it is rare today. The known serial numbers indicate a production run of about 400 machines, and despite production being stopped since 1908, it was still advertised and sold by the end of 1910.

Salcher got patents for his calculating machine, the so-called ADSUMUDI (after ADdition, SUbtraction, MUltiplication, DIvision), in several countries—Austria (patent AT35115 from 16 Sep 1906), Germany (DE204333 and DE209009), Great Britain (GB190623173 and GB190906657), France (FR370829), and the United States (US974006). Two of the patents Salcher shared with Nikolaus Werle, a merchant from Stuttgart. Some patents (e.g. the American one) are for an improved machine, in which the entire principle of operation has been changed, and that has obviously never been manufactured. ADSUMUDI was produced in Germany by the machine factory of Carl Werner of Villingen (the factory had a branch in Innsbruck), one of the largest watch manufacturers in Germany.  It was a messing device with dimensions 39x30x12 cm, and a weight of 10.8 kg.

The operating principle of this 10-positional calculating machine is quite different from any other mechanical calculator ever manufactured. To move the gears with the result wheels attached to them, it has rectangular plates with a slot in the middle and a gear rack on either side of the slot. Depending on which way the result register moves, the gear engages with the rack on the left or the right of the slot, thus reversing the direction of the result register from addition to subtraction and vice versa. The racks are connected to the spring-loaded setting levers so as soon as they are released, they re-zero themselves and transfer their value to the result. All the rest of the complicated mechanism is designed to engage and disengage the correct side of the rack with the result at the correct time, and to make sure the result register is locked when it is not in engagement with the racks.

#### Biography of Alois Salcher

Alois Salcher was an engineer and businessman from Innsbruck, Tyrol. He was the owner of Innsbrucker Dampf-Teigwarenfabrik (pasta factory), had a machine workshop, and was engaged in the real estate business. Salcher was a fan of technical novelties and in 1896 he demonstrated the first automobile in Innsbruck.

Alois Salcher married Emilie Hruschka (1870-1930), the daughter of the local dentist Josef Hruschka (1843-1913). The Hruschka family, originally from Moravia, was a famous Austrian family of dentists, and Emilie Hruschka became the first female dentist in Tyrol and Austria. Alois and Emilie had two sons—Alois and Hubert (born 1 Jan 1905), who became doctors and Nazi party members and served in the army during WWII.

Besides the above-mentioned patents for calculating machines, Salcher has one more patent—for Bundle seals for barrels (pat. №DE100118 from 1897).

## Josef Uržidil

Pečení holubi nelítají do pusy—Baked pigeons don’t fly into your mouth.
Czech proverb

On 5 February 1893, Josef Uržidil (1854-1922), a railway engineer from Žižkov, a small town in the vicinity of Prague, Austro-Hungarian Empire, received a German patent Nr. 70752 (see DE70752) for Additionsmaschine. The adding machine of Uržidil was a key-operated device with a calculating disc. Besides the granted patent, nothing is known about this device, so most probably it remained only on paper, nevertheless let’s examine the adding machine of Josef Uržidil, using the patent application.

The subject of the invention is an addition machine that is suitable for adding a large number of single-digit numbers. Essentially, this machine consists of a toothed wheel R (see the nearby patent drawing), driven by a spiral spring F, which is held by a pawl i and only rotated when one of the pushbuttons marked with numbers is pressed, the associated pressure lever a connected to this forming a frame b, on which the pawl i is attached, depresses, with which the spiral spring F driving the gear R comes into effect and moves the wheel. A lever e plugged onto pin c through a sleeve d, which can also be rotated about the pin f in the vertical direction, and which has an opening g on the end facing frame b, through which the frame b associated bent rod h is inserted, serves to stop the gear R. It is namely when pressing down the frame b, the lever e is pressed into the teeth of the wheel R, which also takes part in the movement of the wheel. But now this lever e strikes the depressed pressure lever and stops the gear wheel R.

If the pressure lever in question is released, the pawl first jumps into the teeth of the wheel R, and the changed position of the wheel is thus fixed. At the same moment, the lever e comes out of the teeth of the wheel R and is driven back by a leaf spring j mounted on the dial in the direction of arrow 1 (Fig. 2), until it strikes a screw k located in the frame b and is stopped there.

All pressure levers a, each of which only belongs to one digit, can be rotated about the pin l, which forms the pin of the lever; the pushbuttons 1, 2, 3,… (see Fig. 7), which are denoted by the first nine digits, protrude from the upper cover plate m (Fig. 1 and 2) and are screwed into these levers. On the lower side of each pressure lever, a leaf spring n is screwed, which has the purpose of snapping the depressed pressure lever back into its original position when the pressure on the button ceases, these levers being held by a fixed plate 0.

The frame b (see Fig. 5) can be rotated about the pin p and is pressed by the leaf springs qq against the adjusting screws introduced in plate 0 (Fig. 2). The pawl i (see Fig. 4 on an enlarged scale) can be rotated about the pin s in the direction of the arrow. The rotation in the other direction is prevented by an attachment t belonging to the frame b, against which a leaf spring u of the pawl also presses.

#### Biography of Josef Uržidil

Josef Uržidil was born on 7 January 1854, in the village of Šipín, part of Konstantinovy Lázně in the Tachov District of Plzeň Region (or in Ošelín, Stříbro), to a German-Bohemian family. His father, Johann Nepomuk Uržidil (1813–1894) was a rural teacher in West Bohemia, who eventually worked as a head teacher in Bor u Tachov, and also wrote textbooks on arithmetic, national studies, and grammar, played the organ and the violin. His mother Barbara Heinl (1814–1900) from Weseritz (Bezdružice), a town in the Tachov District in the Plzeň Region, was born to a German-speaking Czech family. Joseph was named after his paternal grandfather Josef, who was a farmer in Holýšov, while his other grandfather Wenzel Heinl, the father of his mother Barbara, was a surgeon and worked as a doctor and obstetrician in Bezdružice.

In 1895 Josef Uržidil married in Prague to Elisabeth (Elise, Elsa) Metzelesová, a widow of Jewish origin (born 1854 in Prague, she was previously married to Bernhard Steinitz (1850–1892), a merchant and half-brother of the great chess master Wilhelm Steinitz), who from the first marriage had already brought seven children. Their only common son, Johann Nepomuk Josef Adolf, was born on 3 February 1896, in their apartment at Krakovská Street No. 30/3 (Prague II). Johann (Johannes) Uržidil (see the nearby photo from 1897) became a famous German-Bohemian writer, poet, and historian. Elise died on 7 January 1900. On 29 May 1904, Josef married for the second time, to Marie-Anna Mostbeck(ová), a Czech from Nymburk (b. 1864).

Josef Uržidil was an engineer, who worked many years as a clerk and senior inspector of State Railways of West Bohemia and Prague.

In the spring of 1922, Josef’s son Johannes ​​bought a house for his father in Bezdružice near Konstantinovy ​​Lázní, the home district of Josef. On 24 December 1922, Josef Uržidil died there.

## Caroline Saruba

An intelligent woman is a woman with whom one can be as stupid as one wants.
Paul Valéry

On 22 October 1880, one Caroline Sarúba from Vienna received an Austrian patent Nr. AT4264 (see the patent drawing below) for Calculateur Kolonnen-Addierstift (adding pencil). The machine was put into production by company F. Habereder & Co. of Ferdinand Habereder in Vienna, Griesgasse 26. The adding device of Saruba/Habereder is similar to the earlier Instrument for adding and registering numbers of Charles Corliss from 1868, Adding Pencils of Marshall Smith (patents US175775 and US180949) and John White (US177775) from 1876, and Addirstift of Oskar Leuner from 1877.

The Calculateur of Saruba/Habereder was a portable spiral adder (length 24 cm) with a capacity of up to 329. The input mechanism is based on a (quite a big) wheel. It seems the device was produced in a small series because only several examples survived to the present time (see the nearby picture of an example, sold by Dorotheum auction house in 2017).

We don’t know anything about the inventor of this calculating device—Caroline Sarúba. She certainly used to work for Ferdinand Habereder because there is another patent granted to Caroline Sarúba in Firma Habereder and Co. in Wien—it is German patent №11427 from 1 Feb 1880 for Kaffeemaschine, which was advertised and put into production in the early 1880s.

## Jewrem Ugritschitsch

Be humble for you are made of earth. Be noble for you are made of stars.
Serbian proverb

The German businessman and inventor of Serbian origin Jewrem Ugritschitsch (also known as Jevrem Ugrich) was involved in designing, manufacturing, and selling calculating devices for many years. It seems he started in the middle 1890s because his first patent for Additions- und Multiplikationsmashine is from 10 June 1897 (see German patent Nr.99644). Later Ugrich received quite of few other patents for calculating devices and other machines.

The first calculating machine of Ugrich (see the nearby patent drawing) was an addition and multiplication machine with a series of partially overlapping number disks with corresponding cutouts. It is similar to the earlier calculators of David Roth, Chaim Slonimski, and John Groesbeck.

The disks of Ugrich’s adding machine overlap: the left one is above the right one so that the disk with the highest point on the far left is clearly raised and this calculator has a comparatively high overall height. Each disc has 2×10 input positions and display numbers. The tens carry is carried out alternately by one of the two pins located on each disc. When the number 9 is exceeded or when the tens are carried over, this engages in the sloping webs attached to the underside of the next disc (see Fig. 3 in Fig. 2) and thereby rotates this next disc by 18° or one position further. With such a direct, simultaneous transfer, such large rotation angle losses arise over several points that it would certainly not have been possible to implement it with more than the 4 digital wheels as shown in the patent.

At the beginning of the 20th century, Ugrich designed, patented, and later put into production, several variants of a disk column-adding device (see some of them in the nearby image). These devices were manufactured and sold from 1902/03 and offered until at least 1921 mainly by Ugrich and Dr. Albert Hauff from Berlin, but also by other people and companies. In his initial design Ugrich may have been inspired by Carl Brunner’s patent for a “counting wheel with a spiral” (see patent DE69309 valid from 23 July 1892).

The first variant of Ugrich’s calculator, the model Revisor, is placed on the left hand with the thumb in a ring and the 4 fingers in the grip groove on the input field. Then one can add or subtract single-digit numbers from 1 to 9 in the input area for column addition. The pointer in the slot moves continuously along the spiral path until it reaches the next hundred value with one full revolution. The numerical value of the result up to 99 can be read in the display window at the outer end of the slot. The device is very simple and cheap to make, it only cost 3 marks, about a day’s wages. It consists of only 11 individual parts: 3 punched sheets (2 of which are formed), a sliding slider, a thumb ring with its holder, and 5 rivets. According to advertising, one can enter 10000 items in an hour or 7 numbers in 1 second, quite a brisk operator 🙂 One can also add numbers of any size. This applies to all column adders if you remember or write down the intermediate results of each column to be added and (after deleting the result display) continue the calculation with the next column.

The first patent (in fact, it was a Gebrauchsmuster, German utility model, a patent-like, intellectual property right protecting inventions), DRGM 172544 for his spiral adder Ugrich got on 23 April 1902, for an “adding apparatus with a disc containing a number scale and adjusting a slide indicating the ‘hundreds’ when it rotates.” Later he registered several other improved devices: DRGM 257529 from 16.08.1905, DRGM 269765 from 14.02.1906, DRGM 341153 from 11.06.1908, DRGM 439699 from 09.11.1910, DRGM 452861 from 01.03.1911, DRGM 473847 from 09.08.1911. In 1913 Ugrich patented (DRGM 540480 from 12.02.1913) a key-operated calculator—a small calculating machine with a series of number disks, which are connected by shafts to the buttons, each with ten holes and a pointer. Variants of the spiral adder of Ugrich were made and sold in France, England, Sweden, Russia, Austria, and Norway, and got several gold medals at exhibitions.

#### Biography of Jewrem Ugritschitsch

Jewrem Ugritschitsch was born as Јеврем Угричић on 12 May 1867 in Belgrade, Serbia. He was the elder son of the civil engineer Dragoljub Ugritschitsch (Драгољуб Јевта Угричић) and his wife Anna Mikhailovich (they had two sons—Јеврем and Јевта, and two daughters—Милица and Ружа). Anna Ugritschitsch, born in 1852, died 6 September 1901 in Berlin and was buried in the Tegel Orthodox cemetery, was probably his mother. Ugritschitsch was a prominent family from Smederevo, as Dragoljub was the eldest son of Јевтимије Угричић (1800-1886)—a famous Serbian magistrate and politician from the middle 19th century.

We don’t know when Jewrem Ugritschitsch moved to Germany, but it must have been early in his life because, in his first patent application of June 1897, he is specified as Dr. Jewrem Ugritschitsch in Charlottenburg. We don’t have information on what kind of doctorate he had. In  1903 Ugritschitsch changed his last name to Ugrich “through ministerial name change approval.” At the same time, he started his own business for manufacturing and selling calculating machines. Ugrich also tried his hand as an inventor and model maker with the “mechanical workshop of J. Ugrich” from at least 1905 to 1910. His entries in the Berlin address books from 1905 to 1909 contain the keywords “Patented Novelties”, “New Products Sales” and “Patented Novelties and Calculating Machines”. It seems Ugrich abandoned this venture in the late 1910s because in 1919 his occupation was specified as “merchant”.

Ugrich married the teacher Luise Helene Minna Margarete Wernaer (born on 1 December 1884 in Berlin) on 21 December 1904. They have one son, Robert, and two daughters (one of them was Heidi Anna Minna, who was born on 13 July 1905).

Besides the above-mentioned patents and utility models related to calculating machines, Ugrich had also: DRGM 225862 dated 15 June 1904 for a Polishing apparatus with two bowls; Patent DE203850 from 14 October 1908 for a Device for folding sheets of paper using two plates. In addition, Ugrich advertised his duplicating machine Ugrograph or AHA from 1911.

Around 1920 Ugrich moved with his family to his home country, Serbia, where he was appointed as a judge. Because of a serious illness (cancer or stomach ulcer), he committed suicide around 1930 in the desire to ease the burden of care for his family.

## Emile Grandjean

The difficult is what takes a little time. The impossible is what takes a little longer.
Fridtjof Nansen

On 2 February 1864, Emile Grandjean, a French watchmaker (horlogère) from Fumay (Ardennes), received a 15-year patent (see French patent N°61637) for an adding machine, called Additionneur Grandjean. The Scottish pastor Brown’s Rotula Arithmetica from the 1690s can be seen as the archetype of all of these concentric toothed-disk-adding devices. Besides the patent application, nothing is known about Additionneur Grandjean, so most probably it remained only on paper, but its principle was implemented several decades later in quite a few simple adding devices like French l’Infaillible, German Revisor, Union, Optima, Maxima, Duplo, and Triplo by Jewrem Ugritschitsch and Dr. Albert Hauff from Berlin, English Adal, and others. Let’s examine one of the Grandjean-like devices—the Adal Calculator.

The spiral mechanical calculator, called Adal Calculator, was produced in the early 20th century (1907-1915) by Adal Company, Temple Courts, Birmingham (ADAL is formed from the first letters of the names of the company owners—Armand Dreyfus and Alfred Levy, German Jews, who lived in England). It is a single-row adding machine with a diameter of 197 mm, 5 mm thick, 117 gr. weight, which consists of a pair of metal disks and a cursor. The base is a flat aluminum disk with the numbers 00 to 99 around an outer ring which forms a lip. Concentric with this disk, and laid upon it, is a thin brass disk which has one hundred small semi-circular indents and the numbers 00 to 99 in a ring around it. The main part of the upper disk is formed into a spiral of 11 turns. There is a tongue of brass attached to the central bolt, that has a slot in which a steel ball slides as it accumulates turns of the spiral disk. The slot of the tongue has the numbers 1 to 11 marked on it at intervals equivalent to the step between adjacent turns of the spiral. At its further end is a small clamp that holds it at the zero point of the outer ring so that it acts as a stop for the rotation of the accumulating spiral disk.

The whole calculator is held in the flat of the hand. It is a simple adder to 1199 with addends 1-99. The spiral disk is turned by a stylus set into the indent of the number to be added until it reaches the stop. As each number is added the spiral disk rotates and the small steel ball slides in the slot in the tongue indicating the hundreds count of the accumulated result. The total result is thus the number indicated on the tongue (being the hundreds digit) plus the number indicated in the end gap of the stop.

The Adal Calculator was patented in Great Britain (patents GB190705779 and GB190900621), the USA, and Canada (see the first US patent). It seems Dreyfus and Levy bought the rights for the design from Ugritschitsch and were allowed to serve the English and American markets. In 1909, the Addall Co. was incorporated in New York to manufacture the calculating machine.

## Eric Arthur Johnson – touch screen

For every problem there is a solution that is simple, clean, and wrong.
Henry Louis Mencken

The concept of the finger-driven touchscreen interface was put into words in 1965, by the British engineer Eric Arthur Johnson. He worked at the Royal Radar Establishment in Malvern, England, and was interested in developing a touchscreen for air traffic control, as the UK National Air Defense was in need of a solution that would accelerate response time, minimize workloads, and allow for more accurate decision making for air traffic control operators.

In August 1965 Eric Johnson filed his first patent application, which was amended in 1966, and the complete specification was published on 26 November 1969 (see GB patent No. 1172222). In 1969 Johnson received also a US patent for his invention (see US patent Nr. 3482241).

In October 1965 Johnson described his ideas for a capacitive Touch Sensitive Electronic Data Display in a short 2-page article (Touch Display—A novel input/output device for computers. Electronics Letters, 1(8), 219-220). In 1967, he published another more comprehensive paper on the topic (Touch Displays: A Programmed Man-Machine Interface. Ergonomics, 10(2), 271-277), explaining how the technology worked through diagrams and photographs of a prototype. He also foresaw that the design could work as a keyboard for entering characters.

The touchscreen of Johnson was a device that used wires, sensitive to fingers’ touches, on the face of a cathode-ray tube (CRT) on which the computer could write information. His design consisted of a glass-coated insulator with a transparent conductor made of indium tin oxide. Thin copper wires placed across a computer’s CRT allowed the circuits to sense when they were being touched. Interestingly, although Johnson published the idea in the middle 1960s, it wasn’t made a reality or used by British air traffic controllers until the 1990s.

The next step was made in early 1972, by a Danish engineer working in CERN, Bent Stumpe (born 1938). He was asked by Frank Beck, who was in charge of the central control hub in the Super Proton Synchrotron, SPS, control room, to build the hardware for an intelligent system that, in just three console units, would replace all those conventional buttons, switches, etc.

In March 1972, after a few days, Stumpe presented a hand-written proposal to build a touch screen with a fixed number of programmable buttons. It also uses a tracker ball as a computer-controlled pointing device—something like a mouse—and a programmable knob.

“We had very little time to design the new system and demonstrate that both the hardware and the software could really work”, recollected Bent Stumpe. “Thanks to Chick Nichols from the CERN EP workshop, it was possible to evaporate a very thin layer of copper on a flexible and transparent Mylar sheet. This allowed us to produce the very first prototype of a capacitive touch screen.”

The first touchscreens, developed by Bent Stumpe, were installed in CERN in 1973 and remained in operation until 2008.

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## Christopher Strachey

It is impossible to foresee the consequences of being clever.
Christopher Strachey

Christopher Strachey (1916–1975) was a British computer scientist, one of the founders of denotational semantics, and a pioneer in programming language design and computer time-sharing, also been credited as possibly being the first developer of a video game.

Strachey was born to a prominent English family. Stracheys belonged to the Bloomsbury Group whose members included Virginia Woolf, John Maynard Keynes, and Christopher’s uncle Lytton Strachey. At 13, Christopher went to Gresham’s School in Norfolk, where he showed signs of brilliance but in general, performed poorly. Then in 1935, he was admitted to King’s College, Cambridge (just as Alan Turing), where he studied mathematics and then transferred to physics, but continued to neglect his studies. At the end of his third year at Cambridge, Christopher suffered a nervous breakdown, possibly related to coming to terms with his homosexuality. He returned to Cambridge but managed only a “lower second” in the Natural Sciences Tripos.

In 1940, Strachey joined Standard Telephones and Cables (STC) as a research physicist, where he saw a calculating machine—a differential analyzer, which sparked his interest and he began to research the topic. After the war, he became a schoolmaster at St Edmund’s School, Canterbury, and three years later he was able to move to the more prestigious Harrow School in 1949, where he stayed for three years.

In early 1951, Strachey began his career as a programmer, using a reduced version of Turing’s Automatic Computing Engine (ACE) the concept of which dated from 1945: the Pilot ACE. In his spare time, Strachey developed a program for the game of draughts (also known as “checkers”), which he finished a preliminary version in May 1951. The game completely exhausted the Pilot ACE’s memory. The draughts program tried to run for the first time on 30 July 1951 but was unsuccessful due to program errors. When Strachey heard about the Manchester Mark 1, which had a much bigger memory, he asked his former fellow student Alan Turing for the manual and transcribed his program into the operation codes of that machine by October 1951. By the summer of 1952, the program could “play a complete game of Draughts at a reasonable speed”. It may have been the first video game.

In 1951 Strachey programmed the first computer music in England and the earliest recording of music played by a computer—a rendition of the British National Anthem “God Save the King” on the Ferranti Mark 1 computer. During the summer of 1952, Strachey programmed a love letter generator for the Ferranti Mark 1 which is known as the first example of computer-generated literature.

In 1959 Strachey developed the concept of time-sharing, and filed a patent application in February of that year, and gave a paper “Time Sharing in Large Fast Computers” at the inaugural UNESCO Information Processing Conference in Paris where he passed the concept on to Joseph Licklider.

## Joshua Lederberg

The most disastrous thing that you can ever learn is your first programming language.
Alan Kay

In the early 1960s, the biologist Joshua Lederberg (1925-2008), a 1958 Nobel Prize laureate for his discoveries of genetic transfer in bacteria, started working with computers. Over the summer of 1962, he learned to program on BALGOL (Burroughs Algol) for the Burroughs 220 computer (a 1957 vacuum-tube computer with core memory) and quickly succumbed to the hacker syndrome. Lederberg soon became tremendously interested in creating interactive computers to help him in his exobiology research. Specifically, he was interested in designing computing systems to help him study alien organic compounds.

As he was not an expert in either chemistry or computer programming, Lederberg collaborated with two other prominent Jewish-American scientists from Stanford—chemistry professor Carl Djerassi (1923-2015) to help him with chemistry, and the chairman of Stanford computer science department Edward Feigenbaum (b. 1936) with programming, to automate the process of determining chemical structures from raw mass spectrometry data. Feigenbaum was an expert in programming languages and heuristics (in the late 1950s he developed EPAM, one of the first computer models of how people learn) and helped Lederberg design a system that replicated the way Djerassi solved structure elucidation problems. They devised a system called DENDRitic ALgorithm (Dendral) that was able to generate possible chemical structures corresponding to the mass spectrometry data as an output.

DENDRAL (see a historical note), the first expert system in the world, was written in the Lisp programming language of John McCarthy, which was considered the language of artificial intelligence (AI) because of its flexibility. DENDRAL ran on a computer system called ACME (Advanced Computer for Medical Research), installed at Stanford Medical School in 1965 for use by resident researchers through time-sharing.

The project consisted of research on two main programs Heuristic Dendral (see the description) and Meta-Dendral, and several sub-programs. Heuristic Dendral is a performance system and Meta-Dendral is a learning system. The initial program was coded by the programist Georgia Sutherland, but later the Dendral team recruited Bruce Buchanan to extend the system. Buchanan wanted Dendral to make discoveries on its own, not just help humans make them. Thus he, Lederberg, and Feigenbaum designed “Meta-Dendral”, which was a “hypothesis maker”.

The greatest significance of DENDRAL lies in its theoretical and scientific contribution to the development of knowledge-based computer systems. Many later expert systems were derived from Dendral, including SUMEX, MYCIN, MOLGEN, PROSPECTOR, XCON, and STEAMER.