Abstract: A method for measuring the freezing point of a liquid utilizing non-adiabatic thermodynamics for the chilling chamber. The temperature of the chilling chamber in which the measurement is made is actively altered to reduce net heat flow from the sample portion of the liquid being measured at least during nucleation of the sample portion. By actively altering the chilling-chamber temperature, the thermodynamics of the sample itself more nearly approach a true adiabatic condition during nucleation. Preferably, the freezing-point measurement is made in the sample-handling or pick-up device itself.

Abstract: A system for previewing and projecting slides that are stored in spaced, co-planar relation in a planar holder is disclosed. The slides are previewed, either individually or in a group, in their natural orientation without removing the slides from the holder. Projection of the slides to form a naturally oriented image also is accomplished without removing the slides from the holder. In the preferred embodiment, means are provided for moving the planar slide holder orthogonally with respect to the optical axis of the projection system. A slide indexing system is provided to allow the projectionist to select a particular slide for projection. The slide indexing system utilizes cooperative means on the slide holder and projector to achieve indexing and, if desired, other control functions. In an alternative embodiment, the projected image plane is vertical and can be rotated about a vertical axis at the projector without moving the base of the projector.