Abstract: A recording material comprising (1) at least one thiazine compound capable of forming a color when contacted with an electron accepting material and represented by the following general formula (I): ##STR1## wherein A.sub.1 and A.sub.2, which may be the same or different, each represents an aryl group or a hetero ring residue or, when taken together, A.sub.1 and A.sub.2 represent a hetero ring or a fluorene ring; ring B represents an aromatic hydrocarbon ring or a hetero ring; and Y represents a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group, a hetero ring residue, an amino group, an amido group, a hydroxy group or a thio group; provided that at least one of A.sub.1 and A.sub.2 or, when A.sub.1 and A.sub.2 are taken together, the ring formed by A.sub.1 and A.sub.2, is an electron donating aryl group, an electron donating hetero ring residue or an electron donating fluorene ring residue; and (2) an electron accepting material.

Abstract: A thiazine derivative, which forms a color on contact with an electron accepting material, represented by the formula (II): ##STR1## wherein A.sub.1 and A.sub.2, which may be the same or different, each represents an aryl group or a heterocyclic group and A.sub.1 and A.sub.2 may combine together to form a heterocyclic ring or a fluorene ring, the ring B represents an aromatic hydrocarbon ring or a heterocyclic ring, and Y represents a hydrogen atom, an aliphatic group, an aryl group, a heterocyclic group, an amino group, an amido group, an oxy group or a thio group, but at least one of A.sub.1 and A.sub.2 or the ring formed by the combination of A.sub.1 and A.sub.2 represents an electron donating aryl group or an electron donating heterocyclic group, and a process for preparing the thiazine derivatives represented by the formula (II) by oxidizing a thioamide derivative represented by the formula (I): ##STR2## wherein A.sub.1, A.sub.2, B and Y are as above described.

Abstract: A recording method and material employing a basic color former component which changes to a colored species by an interaction with a cellulose fiber and has a molecular extinction coefficient of not less than about 100 in an ethyl alcohol solution.

Abstract: A variable stage type carburetor provided with a venturi vane which is adapted to vary the venturi area in a venturi portion thereof, commensurate to the opening of a throttle valve. This carburetor features that, in the running condition where the opening of a throttle valve is considerably large and yet the quantity of intake air is relatively less, the venturi vane is forcedly displaced in a direction to be closed so as to increase the venturi negative pressure in the venturi portion, thereby enhancing the injection of fuel.

Abstract: A 1,3-dihydro-1-oxo-benzo[b]thieno[2,3-C]furan derivative represented by the following General Formula I ##SPC1##or a 1,3-dihydro-3-oxo-benzo[b]thieno[2,3-C]furan derivative represented by the following General Formula II: ##SPC2##wherein ring A represents a benzene ring or a naphthalene ring, R.sub.1 and R.sub.2 each represents an amino group, and X, Y and Z each represents a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkoxy group, an aralkoxy group, an acyloxy group, a nitro group or an amino group, useful as a color former, e.g., in a pressure sensitive copying paper.