Abstract: A measuring device includes at least three elongate sides, each side having first and second ends and a pair of outer edges extending therebetween. Each side includes a channel extending between the first and second ends at each outer edge. The measuring device includes a plurality of strips, the quantity of strips being at least as great as the quantity of all the channels. Each strip includes scaled indicia that is different from scaled indicia of every other strip. A respective strip is removably positioned in each of the channels such that each side has two of the strips offset 180 degrees away from each other. Each side is transparent to allow the scaled indicia of the strips in the channels to be viewed.

Abstract: A measuring device includes at least three elongate sides, each side having first and second ends and a pair of outer edges extending therebetween. Each side includes a channel extending between the first and second ends at each outer edge. The measuring device includes a plurality of strips, the quantity of strips being at least as great as the quantity of all the channels. Each strip includes scaled indicia that is different from scaled indicia of every other strip. A respective strip is removably positioned in each of the channels such that each side has two of the strips offset 180 degrees away from each other. Each side is transparent to allow the scaled indicia of the strips in the channels to be viewed.

Abstract: The “PT RULER”, an improvement on the typical triangular architectural scale ruler, in the following ways: 1) improvement of the view angle of the ruler eliminating the need for the user to “bend over” the ruler, 2) improvement of the arrangement or placement of the scales on the ruler to enable the user to simply “rotate” the ruler to view related scales, 3) improvement of the color of the individual scales, with each scale having its own distinctive color, 4) improvement of the font of each individual scales, using different font sizes for better readability, and 5) improvement of the ruler by changing the 16 scale with a 16? on center scale (based on ¼? scale).

Abstract: Dithiophosphoric acids are advantageously produced by reaction of an alcohol or phenol with phosphorus sesquisulphide in the presence of sulphur, preferably at the reflux temperature of the alcohol used.