# Vladimir Lukyanov’s Water Computer

Early computers were mechanical machines built using gears and levers. These parts or components could be moved with precision and were connected to other components in a way that simulated the relationship between different variables in a mathematical equation. By moving a gear or pulling a lever, one can change these variables and the results of these actions can be viewed in another set of gears, whose newly acquired positions gave the answer the operator was seeking.

In 1936, a Russian engineer named Vladimir Lukyanov built such a mechanical computer that used not gears and levers but water to compute.

*Vladimir Lukyanov’s water integrator.*

Lukyanov was one of the engineers working on the construction of the Troitsk-Orsk and Kartaly-Magnitnaya railways in the late 1920s. To ensure the quality and durability of reinforced concrete structures, the engineers poured concrete only in the summer. Despite this, cracks still appeared in the concrete when temperatures dropped below zero in winter. Lukyanov suggested that this can be avoided if a careful analysis of the temperature changes in the concrete mass is made, depending on the composition of the concrete, the cement used, the technology of the work, and the external conditions. Lukyanov began studying temperature conditions in concrete masonry, but the existing calculation methods could not give a quick and accurate solution to the complex differential equations that described the temperature regime.

In search of a new approach to solving the problem, Lukyanov discovered that water flow is in many respects similar in its laws to the distribution of heat. He concluded that by building a computer where the main component was water, Lukyanov could visualize the invisible thermal process. In 1936, Lukyanov built the first model of his “water integrator” at the Institute of Way and Construction (now Central Research Institute of Transport Construction, or TsNIIS). At that time it was the only computer that could solve partial differential equations.

Lukyanov’s water integrator was an impressive piece of plumbing. It was about the size of a closet, and consisted of several interconnected pipes and pumps. The water level in various chambers represented stored numbers, and the rate of flow between them represented mathematical operations. The result was neatly plotted in a graph.

The early models of the water integrator were crude made of roofing iron, sheet metal and glass tubes and were used only for calculations in the field of heat engineering. Newer models were able to solve more complicated problems which significantly expanded its application. In the 1950s, an integrator was built whose parts could be removed and combined in different configuration depending on the nature and complexity of the problem being solved. The application of the water integrator became so broad that the machine was mass produced for use in laboratories and educational institutions across the Soviet Union. They were used in a wide range of applications, such as solving construction issues in the sands of Central Asia and in permafrost, in studying the temperature regime of the Antarctic ice sheet, solving problems in rocket science, and so on.

Lukyanov’s water integrator remained relevant, despite the availability of electronic computers, for a surprisingly long time. It was only in the 1980s, with the development of smaller and high speed digital computers, that the capabilities of the water integrator began to look dated.

At present times, only two Lukyanov water integrators exist, stored in the Polytechnic Museum in Moscow.

*Vladimir Lukyanov’s water integrator. Image credit:*

*www.kramola.info*

*Vladimir Lukyanov’s water integrator. Image credit:*

*www.kramola.info*