to fill the trowel of a plasterer. Who is the Tana that holds that sand is an improvement on plaster? Said R. Hisda: R. Jehudah of a Boraitha (Baba Bathra, 60b); Rabha, however, said it may be also in accordance with the rabbis, as they hold that the spoiling (of the whiteness) of the plaster (through the admixture of sand) is an improvement of its durability.
"For reed as much as is required to make a writing-pen." A Boraitha teaches: A pen that reaches the joints of the fingers.
"Or should it be thick." A Boraitha teaches: To fry a beaten egg mixed with oil. Said Mar b. Rabhina to his son: "Didst thou ever hear what is understood by the softest egg?" He answered that R. Shesheth said it was a hen's egg, Why does the Mishna call it a light (soft) egg? Because the sages found that no eggs are cooked as quickly as pullets' eggs. Why is it that all other prescribed quantities prohibited to be carried out on the Sabbath are of the size of a dried fig, and here the quantity is of the size of an egg? Answered R. Na'hman: "Even here is meant the quantity of a dried fig from an egg."
Mishna IV.: The quantity of a bone is that large enough to be made into a spoon—R. Jehudah says large enough to be made into a key; glass of sufficient size to be used for scraping off the points of a weaver's spindles; a splinter or a stone large enough to throw at a bird—R. Elazar b. Jacob says to throw at an animal.
Gemara: Is it to be understood from the Mishna that the prescribed quantity allowed by R. Jehudah is larger than that allowed by the rabbis? Is it not a fact that the rabbis allow the larger? Said Ulla: (R. Jehudah refers to) the tooth of a key.
"Glass of sufficient size," etc. A Boraitha states: Sufficient glass to cut two threads at once.
"A splinter," etc. Said R. Na'hman in the name of R. Johanan: "Provided it is large enough to hurt." But how large should it be? R. Elazar b. Jacob teaches in a Boraitha: The weight of ten zuz.
Zunin once entered the college and questioned the teachers. "What is the prescribed quantity for gravel used in privy for toilet purposes?" He was answered: "The equivalent in quantity to the size of an olive, a nut, or an egg." Said he: "It would then be necessary to carry along a scale." So they deliberated, and decided that the quantity should be a handful.
Rabba b. R. Shilla asked of R. Hisda: "Is it permitted to carry up gravel to the roof (for the purpose cited above, as it is
