Formal prepositions of method (посредством, при помощи)

When describing scientific processes or precise methods, Russian uses formal compound prepositions. These prepositions require the Genitive case.

By Means Of: посредством

To describe the instrument or medium used to achieve a result, use посредством (by means of). It is frequently found in technical or formal writing.

The scientist changes the direction of the light by means of this lens.
Учёный меняет направление света посредством этой линзы.

With the Help Of: с помощью and при помощи

More common ways to express method or instrument are с помощью and при помощи (with the help of / using). They are interchangeable and also take the Genitive case.

With the help of a prism, we divide white light into a spectrum.
При помощи призмы мы делим белый свет на спектр.

Describing Optical Systems

These formal prepositions comfortably fit into complex sentences describing how optical devices manipulate light or study a spectrum.

With the help of the spectrum, scientists can find out how the prism refracts light.
С помощью спектра учёные могут узнать, как призма преломляет свет.