Abstract: A novel and improved surfactant modified silica and method for making the same. The surfactant modified silica is characterized as a fumed silica having a surfactant material treated therewith. Also disclosed is process of thickening aqueous systems which includes the addition of an effective amount of a fumed silica having a surfactant material treated therewith.

Abstract: Hand-eye coordination while tracking a changing size image is measured by a method that includes: displaying an image that is varied in size in response to a programmed signal; having the person under test manipulate a manual control that effects image size change by cancelling the effects of the programmed signal; and, comparing the tracking response with the image size change, the difference therebetween being a measure of the subjects' hand-eye coordination. The image can be randomly displaced laterally during test and its light intensity parameters can be varied. Image size change is programmed in various ways including randomly occurring reversals in direction of change. The method is implemented by means of an image figure generator that provides a rectangular image on the screen of a CRT. A programmable image size change circuit controls the size of the rectangle in concert with a potentiometer circuit that is manually controlled by the test subject.