Abstract: Disclosed is a supportive chair for sitting comfortably at low heights above and relative to the ground. Preferably, the chair comprises a primary seating surface and a secondary seating surface curving around the rear of the primary seating surface to provide additional support for the user. It is preferred that the secondary seating surface be inwardly and downwardly sloped and provide a low lateral boundary for the user, thereby promoting proper alignment of the buttocks on the primary seating surface. Thus, the chair raises the buttocks and hips of the user off of the seating level, creating a relative height difference between the hips and legs. This raising of the hips relative to the legs creates a sitting posture that promotes vertical back alignment. As a result, the user is able to comfortably maintain this position with a reduced amount of back muscle strain, allowing prolonged comfortable seating periods.

Abstract: The present invention relates to a wet process for the manufacture of phosphoric acid, which process essentially comprises a digestion step in which phosphate rock is digested by means of phosphoric acid and sulfuric acid to form a slurry containing highly concentrated phosphoric acid together with calcium sulfate hemihydrate, and a separation step in which the slurry is filtered for separation of calcium sulfate hemihydrate from the highly concentrated phosphoric acid (in which the concentration of P205 in the product acid is higher than 40% by weight, based on the weight of the product acid) and which is characterized by supplying active silica at a ratio of 0.2-5% by weight, based on the weight of phosphate rock, in order that active silica may be present in the above mentioned digestion step.