A calendar that determines the beginning and end of the gestation of different animal species (Machine-translation by Google Translate, not legally binding)

摘要

A determining calendar of the beginning and end of the gestation of the different species of animals, which is composed of two discs of any material, well paper, cardboard, celluloid, metal etc., which meets the appropriate conditions to be able to print them. the elements that with precise for the case or to adhere to them another matter on which those printed ones go. These two discs, are of different diameter, going superimposed so that the largest of them is below and joined together by means of an axis that imprisoning them in the way that is best allows the rotation or rotation of them. (Machine-translation by Google Translate, not legally binding)