or - 40° Fahrenheit to Centigrade,
F. = - 40°, (- 40° - 32°) = - 72°,
whence - 72° × ⁵/₉; = - 40° C.
—From “The Microscope” (by S. H. Gage) by permission.
Footnotes:
[1] For apparatus, reagents, collection and preservation of material, etc., see Appendix.
[2] If spirogyra is forming fruit some of the threads will be lying parallel in pairs, and connected with short tubes. In some of the cells there will be found rounded or oval bodies known as zygospores. These may be seen in [fig. 86], and will be described in another part of the book.
[3] The most suitable preparations of mucor for study are made by growing the plant in a nutrient substance which largely consists of gelatine, or, better, agar-agar, a gelatinous preparation of certain seaweeds. This, after the plant is sown in it, should be poured into sterilised shallow glass plates, called Petrie dishes.
[4] We should note that the coloring matter of the beet resides in the cell-sap. It is in these colored cells that we can best see the movement take place, since the red color serves to differentiate well the moving mass from the cell wall. The protoplasmic membrane at several points usually clings tenaciously so that at several places the membrane is arched strongly away from the cell wall as shown in [fig. 24]. While water is removed from the cell-sap, we note that the coloring matter does not escape through the protoplasmic membrane.