In this article we'll consider the history of the vertical bar's loss of stability problem. Let some force directed along the bar's axis acts on vertical bar which height is greater than its cross section's length. It's necessary to find the value of this force, from which the bar will start to curve.

Before XVIII century such problems had been solved empirically. The first mathematical decision of this problem belongs to L. Euler. He derived a theoretic formula and considered its versions in case of different fixing ways.

Nevertheless Euler's formula works only for flexible bars and non-eccentric load. First it was found out by I. Hodkinson, an English engineer and a member of Manchester's scientific community. Few later on a base of Hodgkinson's experience A.E.H. Love, an Oxford Professor, also derived an empirical formula. But its drawback is that there's no dependence of numeric coefficients on properties of the material in the formula.

In 1845, a Belgian engineer Е. Lamarl first set a limit to applicability of the Euler's formula. He offered to take the critical tension of flexible bars to be equal to yield limit. Subsequently, the Euler's theory of stability was tested in the experiences of J. Bauschinger and L. Tetmajer. Bauschinger, a German engineer, worked at this problem in the Munich Polytechnic laboratory. As a result of the test Bauschinger found out that because of different errors the sample was starting to curve at the small value of compressing force. This value is very close to the critical one, computed by Euler in condition that tension, conformed to this force, is less than the proportional limit at compressing.

In 1890 L.von Tetmajer, a Professor of Polytechnikum in Zurich, made experiments at stability of compressed iron bars with different cross sections. In 1889 F. Engesser, a German engineer, offered to compute a critical tension by Euler's formula having changed an elastic modulus by tangential modulus. Experimental definition of critical forces for compressed bars was made repeatedly.

The most comprehensive material was compiled by F. Jasinski. He initiated the modern methods of computing the compressed bars stability. F. Jasinski was a Professor at the Saint-Petersburg Institute of Civil Engineers. In 1895 Jasinski and Tetmajer, on a base of experimental knowledge offered an empirical linear formula for computing the critical tensions.

Nowadays, attempts at theoretic solution of this problem are continuing.