Abstract: A vermiculite composition capable of exhibiting a high degree of volume increase upon subjection to thermal exfoliation composed of vermiculite mineralogical species having specific gravity of from 2.5 g/cm.sup.3 to 2.9 g/cm.sup.3. Further, intumescent sheets formed with said vermiculite composition exhibit low initial expansion temperature and very high maximum expansion properties.

Abstract: A vermiculite composition composed of particulate vermiculite mineral species having a density of 2.3 g/cm.sup.3 to 2.7 g/cm.sup.3 which has intercalated cations of lithium or organo ammonium and to dispersions obtained therefrom.

Abstract: The improved virus titration and identification system of the present invention comprises a transparent plate having a plurality of spaced wells arranged in a plurality of spaced rows. A dried, preferably freeze-dried, amount of viable specific virus antiserum or a dried, preferably freeze-dried, amount of normal serum is disposed in each well. All wells containing a given specific antiserum are aligned in a single row of a given direction and all of the rows which contain antiserum are aligned with each other.In one embodiment, the system includes a reference locator disposed on the transparent plate and movable relative thereto. The locator comprises a sheet defining a pair of intersecting light-transmitting windows of specific length. Such windows may be slots in the sheet and may intersect each other at about their mid-points. Preferably, the plate has the wells arranged in a rectangular pattern, so that there are rows of wells in two different orientations at about 90.degree.