Abstract: An improved teaching device which aids abstract learning through visual and practical application. The device has three compartments which are enclosed with transparent face and back plates, a base, a top plate and side walls. Two interior plates and the side walls form the three compartments where one of the plates mounted on the base does not reach the top plate so that the two compartments it forms are not sealed off. The third compartment is formed by an interior plate mounted on the base and reaches the top plate, forming a common wall between one of the two previous compartments and the third compartment, and sealing of the third compartment. Enclosed in the third compartment is a number of items, such as marbles, the number of which are the sum of similar items dispersed in the two previous compartments.

Abstract: A pressurizing and closure apparatus for carbonated beverage containers. The apparatus is inserted and secured to the container's mouth and a hand pump pressurizes the container to a pressure greater than the surface pressure of the carbonated beverage. A valve then seals the pressurized container from the pressurizing apparatus as the hand pump is slightly withdrawn from its bottom position.

Abstract: An improved retractible fly tying bobbin having means for maintaining tension on the thread while tying the fly and also means for quickly relieving all the tension on the thread when the tying is completed. The bobbin is compact and utilizes two cupped shaped cylindrical halves which engage each other in a drive fit, wherein one cylindrical half is driven and the other half is the driver, tension on the thread can be adjusted prior to assembly of the bobbin to keep the thread taught while winding without causing the thread to break.

Abstract: A method of producing long life precision abrasive articles for use in metal removal operations. In this method abrasive particles are impinged against the inner surfaces of a rotating cylindrical mold by centrifugal force. During rotation of the mold a metallic matrix is deposited electrolytically on the inner surfaces of the mold until a matrix supporting the abrasive particles is formed. The matrix is then removed to receive core material and the core is then machined to the finished dimensions. The method is carried out at low temperatures, thereby avoiding heat distortion of the end product.

Abstract: A tape reel holder, made from a single piece of metal to hold a tape reel straight and taut so as to allow one man to lay out measurements over a great length without the necessity of a helper to hold the tape reel securely.