In this text I propose to analyse the contributions of the Russian, Moscow-based, philosopher and pedagogue Tsezar Pavlovitch Baltalon (1855–1913) to psychological aesthetics. The experiments he organized took place in the first Psychological Laboratory of Moscow University in 1900. The repetition of Fechner's experimental protocols with rectangles and the inclusion of new experimental insights into raised hypotheses permitted him to conclude that the aesthetic pleasure that comes from the perception of geometric forms does not depend on their formal mathematical properties and proportions. The geometric shapes organized according to different mathematical relations could cause similar impressions of aesthetic pleasure or, on the contrary, forms with equal mathematical proportions could cause displeasure. The aesthetics of geometrical shapes could scarcely be confined to psychology merely as the aesthetics of spatial relations. It should be understood mainly as the aesthetic of visual, motor, and other perceptions that occur as a consequence of a combination of sensations and feelings.