As we continue to think about the ship sailing on Shabbat, we have questions about height and distance.
Remember our Mishnah:
IT ONCE HAPPENED THAT THEY WERE COMING FROM BRINDISI AND WHILE THEIR SHIP WAS SAILING ON THE SEA, R. GAMALIEL AND R. ELEAZAR. B. AZARIAH WALKED ABOUT THROUGHOUT ITS AREA BUT R. JOSHUA AND R. AKIBA DID NOT MOVE BEYOND FOUR CUBITS BECAUSE THEY DESIRED TO IMPOSE A RESTRICTION UPON THEMSELVES.
Now, what was the reason that Rabbis Joshua and Akiba while allowing that movement was allowed added a restriction on themselves? Maybe it had to do with height.
R. Hanania enquired: Is the law of Sabbath limits applicable at a height above ten handbreadths from the ground or not?
A ship at sea, of course, rides the swells which can certainly go 10 handbreadths over the level sea. So do they leave any potential Shabbat restrictions in those moments? And if so – what about other circumstances – like flying?!
The question, however, arises . . . where one moves by means of a miraculous leap
Lest you think this hypothetical in an era over a thousand years before the Wright Brothers. Let’s not forget Elijah:
Come and hear: Who was it that delivered the seven traditional rulings on a Sabbath morning to R. Hisda at Sura and on the same Sabbath evening to Rabbah at Pumbeditha? (Far beyond the Shabbat travel limit) Was it not Elijah who delivered them, which proves, does it not, that the law of Sabbath limits is inapplicable above ten handbreadths from the ground?
Well, maybe not:
It is possible that the demon Joseph delivered them.
A discussion then ensues about the questions of what days the Messiah will or will not arrive on.
But let’s end with something a little more scientific. The Mishnah also notes that Gamliel was able to determined the precise distance of the ship from shore. Clearly he had an instrument which allowed him to do so. (According to some sources he knew the height of a tower on shore and by calculating the angle of his observation could figure out the distance. A surveyors technique clearly well known:
Tanna taught: R. Gamaliel had a tube through which he could see at a distance of two thousand cubits across the land and a corresponding distance across the sea. If a man desires to ascertain the depth of a ravine let him use a tube and by looking through it be in a position to ascertain the depth of the ravine, and if he wishes to ascertain the height of a palm-tree let him measure his own height and the length of his shadow as well as that of the shadow of the tree, and he will thus ascertain the height of the palm-tree.
Geometry at work in the Talmud!