1936 Volume 7 Issue 1 Pages 137-146
When the various states of cell tissues are pressed by the outer physical force, the tissues are contracted against pressure, with correspondence to the states of the cell tissues. This hardograph is an apparatus which makes the process of the contraction of fruit tissues into the graph and determines the hardness by this graph. The fruit tissue which was taken from the fruits in the same size (in volume and shape) were compressed by the accumulating gravity of water which was poured in constant volume per minute, and a receiving bottle of the dropping water was hanged on one end of a movable beam such as a balance and the beam was balanced by the weights which were hanged on the other end, and a piece of the fruit tissue whithin the metal plate connected with the beam and the fixed metal plate, was compressed by the gravity of water in the receiving bottle and the tissue was contracted.
This contraction is figured by a kymograph, and a curve is produced between the two axes of contractibility (milimeter) and pressure (kilogram) by the gravity of accumulating water in the receiving bottle. This curve is only a line, to the tissue is broken and falled down by the pressure, and the value of the hardness is shown by an angle θ° between a horizontal axis and a straight line connected the point and an end point of the curve, and the angle was determined the ratio of kilogram and milimeter, that is, cotθ°.
This method determined not only the hardness of the tissue, but presumed the various conditions of the tissue, and the special case was shown, that is, the curves which have different types not withstanding their curves have the same value of hardness. Such a case was found when the hardness were determined by this method among the various stored apples. These curves seem to make the relation between the curve and the texture clear so that when the points where the curves are crossed by the straight lines are in different level, the level of the crossed point is the lower, its texture is the better, and the level is the higher, the texture is the worse.
As the fruit tissue was frozen, warmed or dried, the curves showed the typical forms corresponding to their tissues which were suffered those physical changes, and by the bases of these experiments, the suitable harvesting periods for the storage of the apples of Manchuria was studied, and the apples (Newtown) of Oregon U.S.A. were imported at Shanghai and arrived at this Station on 28th January in this year were tested. It was presumed, by this method, that the texture of apples showed almost no change after the transportation.
The difference of the hardness between the blushing and non-blushing side of apple was shown more clearly by this hard ographic method, and it was found that this difference of hardness was caused by the different turgescences of two sides.