Monday, November 14, 2022

The Illumination on the Ark

Back to Noah's Ark! The Torah relates that God instructed Noah to make "tzohar," "illumination," for the ark. What is this illumination? Chizkuni says that the simple explanation is that it refers to preparing oil for lamps. Better known is Rashi, citing the Midrash, who presents two views as what this means. One view is that it was a window (which some commentaries explain to be many windows); the other is that it was a precious stone which provided illumination. The commentaries suggest that the reason for the latter view is that Noah was not righteous enough to deserve to see the punishment inflicted upon the rest of the world, and thus the ark did not have windows. (There are also all kinds of beautiful homiletic explanations of these views.)

Of course, the question that many people will ask here is that surely gemstones only reflect light and do not actually generate it. Accordingly, it would seem that mystics will explain it as a supernatural phenomenon, while rationalists would take it as another example of an incorrect belief about the natural world - and as usual, one that was extremely prevalent in antiquity.

But it's not so straightforward. The Midrash further elaborates: "R' Pinchas said in the name of R' Levi: The entire twelve months Noah was in the ark, he did not need the light of the sun in the day or the moon at night. Rather, he had the gem, and he relied on it. When it was dim, he knew it was day, and when it was bright, he knew it was night."

Now, this initially seems a strange explanation, which is the opposite of what one might expect - surely if the point of the stone was to provide illumination, then it should be bright during the day, not at night. However, the commentaries explain that there was tiny amounts of light entering the ark through cracks in the walls, which meant that the light generated by the gemstone was less noticeable during the day. Only when there was no light at all from outside was the light generated by the gemstone noticeable. (The Midrash says the same about candles that Rav Huna lit in a cave.)

In fact, there are minerals that really can emit light. Some glow when heated (even with slight amounts of heat such as that from one's hand), some provide luminescence under ultraviolet light, while others store light that is received and emit it later. However, the light emitted in such cases is minimal. And yet this may be a viable explanation of the Midrash. Note that the Midrash does not say that the gem was emitting light for enabling activity - it says that the function of the light was merely to demonstrate that it was night-time. Accordingly, when there was no ambient light entering from cracks in the wall, the luminescence of the gem would indeed demonstrate that it was night.

Recently a treasured friend of the museum mentioned a different possibility to me. She told me about a fascinating object called a "deck prism." This was an innovation used to illuminate ships before electricity was invented, and when lighting candles below deck was a fire hazard. A deck prism was a large gemstone cut in such a way that it was flat on one side and multifaceted on other sides. The prism was inserted into a precisely cut hole in the deck such that water would not enter, while sunlight would enter the prism and be refracted in a wide area around the lower part of the ship! They were made in both rectangular and hexagonal shapes, as you can see in these pictures.

This is a fascinating blend of both explanations given in the Midrash, though it is different from each of them. (I just noticed that ArtScroll presents this as being the explanation of Chizkuni and Rashi, but this does not seem correct.) And, as far as I can tell, such prisms were used in the last few centuries but not in antiquity. Still, it's an intriguing explanation, and an interesting way of shedding light on the problem of shedding light below deck! My friend is donating such a deck prism for exhibit in our forthcoming Noah's Ark exhibit.

Meanwhile, if you're able to help us develop this extraordinary exhibit, either by bringing model arks to Israel from the US/ Germany/ Italy/ Africa/ Australia, or by sponsoring arks in the exhibit, please be in touch! I also have a nine-foot hammerhead shark that I need to get from New Jersey to Israel.


  1. This just came up with the kids: We were talking about bat sonar and I said that submarines use sonar as well. "Why don't they have windows?" the kids asked. "Because the water pressure would break them," I said, and mentioned the Ark as an example too. If the Flood was really that strong, a lot of windows on a boat- especially as they hadn't invented portholes yet- would have been a big problem. And if all the Ark did was float, they wouldn't have *needed* windows. Looking out at the world being destroyed, and then at an endless expanse of rain and water, might have been psychologically unhealthy too.

    I'd say that a very well polished crystal can even be transparent, but they probably didn't have that capability yet.

  2. The Wikipedia article that Rabbi Slifkin linked to contains this:

    Rabbinic Judaism includes a number of references to luminous gems. For example, Abraham was allegedly so jealous of his many wives that he incarcerated them in a city of iron with walls so high that neither the sun nor moon could be seen. However, he "provided a great bowl filled with jewels which lighted up the whole building" (Ball 1938: 499). The first century Rabbi, Rav Huna, says he was fleeing from Roman soldiers and hid in a cave illuminated by a light that was brighter in the night and darker in the day.[citation needed]

    The "citation needed" is the Bereshis Rabbah Parshah 31 reference that Rabbi Slifkin linked to as well. But what was this about Avraham imprisoning his jealous wives? Where is that from? Avraham never had more than two wives at any one time!

    1. You can find the original here: (flip to page 20). He brings no sources. There is a reference to the Ark in the next column.

      The only luminous stones I can think of are the healing one Hashem is said to have put in the sun, and the choshen. Both are of course miraculous.

    2. Okay--Maybe he intended to write "Solomon" instead of "Abraham": "Solomon was so jealous of his wives, and they were not few..."

    3. Maybe, but that's a pretty big and obvious mistake. And I'd still like to know his source.

    4. @Yehudah or anyone, there's an "edit" tab on all wiki pages. If you have the time & energy, edit it appropriately. I've done some minor editing over the years. A big mistake like this deserves to be corrected.

    5. Anonymous: agreed, but it's just such a strange thing that I'd want to know the source before editing it - or even simply deleting it (which is of course also an option - I have undeleted a thing or two on wikipedia)

      -Yosef R

  3. Speaking a bit more midrashically than historically... I lined up three disputes and explained them as being aligned.

    1- Was Noach tamim by normal standards (Reish Laqish) or only compared to his generations (R Yochanan; Sanhedrin 108a, cited by Rashi Bereishis 6:9)?

    2- Was the tzohar a window or a gem? (Bereishis Rabba 31:11, again cited by Rashi)

    Frankly, I didn't consider the possibility that the mainstream would simply accept that gems can internally lit. (Although maybe the radioactivity of the gem is what caused the subsequent biodiversity. ≶grin>)

    Instead, recall that a chalon would have meant an open hole in the wall. The alternative would be a translucent stone in that hole.

    We know from the story of Lot (Bereishis 19:17), when someone is saved in ways they did not deserve, they aren't supposed to be looking at those who didn't get saved. (Rationalists take note: According to Chizquni, Lot's wife turned around to look out at the plain and saw that it had turned to a pillar of salt. Still a miracle, but not as arbitrary as turning a person into salt.)

    An aspect of that machloqes about a tzohar is whether the people in the teivah could have seen the destruction. Had Noach been tamim by any standard, that's a possibility. But if he only was tamim in comparison, it would only make sense for the light to come in through something that blocked his vision.

    3- Light that comes through another substance is generally subject to chromatic aberration; the different colors are bent different amounts. Even without intending to make a prism, it actually takes engineering to avoid some breakdown of white light into spectra when going through a lens.

    Meaning, if the tzohar was a window, the light in the teivah would look normal. If not, there were would be spectra -- little rainbows -- all over the walls.

    And that will change what thoughts arise when we see a rainbow today. What is the sign of Hashem's Covenant with Noach? If Noach deserved to be saved, then his tzohar was a window (hopefully with shutters) and the rainbow was exclusively something he saw after the mabul. The rainbow is a sign of peace.

    But... if Noach didn't deserve to be saved, and his view was blocked by something that made prismatic patterns on the walls of the teiva, then the rainbow is a sign that we are no better. Sitting safely in our place in the world for reasons other than our deserving it.

    And this explains halakhah's (Orakh Chaim 229) conflicted opinion of looking at rainbows.

    1. This is a nice pshat

    2. Anonymous 5:36PM

      A nice Pshat, but is any of it actually true? Perhaps, if our ancient Gedolim were endowed with some curious Ruach HaScience to compliment their Ruach HaKodesh they might have more presumably speculated that Noach was directed to include large quantities of bioluminescent bacteria to generate the artificial light required to survive those perilous 40 days and 40 nights. Why no Ruach HaScience?

    3. They had no need cause they had the Ruach Mofsy.

  4. I think that the book Arguments for the Sake of Heaven by Rabbi Jonathan Sachs should be mandatory reading for everyone on this blog.

  5. An Enlightening and very illuminating article.

  6. FWIW -- from my boating experience --

    Modern deck prisms are made of glass. I doubt that they were _ever_ made of gemstones, since those are too small to be practical.

    I don't know what "crystal" means, in this discussion. If the technology for making, and cutting or molding glass is available, it's _way_ easier to use glass, than to use naturally-occurring crystal like quartz.

    ..... Charles

    1. That's *if* it's available. From what point was it? Not back then, I'm thinking.

  7. "Note that the Midrash does not say that the gem was emitting light for enabling activity - it says that the function of the light was merely to demonstrate that it was night-time. Accordingly, when there was no ambient light entering from cracks in the wall, the luminescence of the gem would indeed demonstrate that it was night."

    If the *only* function was to tell if it was night, and that was achieved by relative ambience then you would have been able to tell *even easier* by simply not having it there at all! When it is pitch black it's night, when there is some light from the cracks it's day. At best that works if the usefulness for telling day from night is a secondary function. But even then it's not a "function" per say as you can tell just as well (better) without it being there. So at best it's a benefit of having only a dim light vs. a stronger light.

  8. How would there be cracks if it was covered in tar?

  9. Great post! Thank you!

    (I don't protest the anti-chareidi posts, but those who do should consider not only complaining when they appear but also express appreciation for those like this one. If you have a specific problem with "while rationalists would take it as another example of an incorrect belief about the natural world" that's something else. Note that RDS gives equal time for the mystic view, while some don't want the rationalist view to get any time at all.)

  10. The museum itself has some of the ark's dimensions. I suggest a large, actual Deck Prism be built into the roof in an otherwise dark area, filled with biblical animals (live/ stuffed/ photos/ etc) in arks or not ...? (Sorry, I can't sponsor.)
    Or allow a guide to turn off the light for a minute or so for people to get a feel of the experience ...?

    Regarding the hammerhead, I'll be water skiing from New Jersey to RBS during winter vacation this year and I have room for a companion. Especially for a hammerhead. They're so easy to tie on.


  11. "I also have a nine-foot hammerhead shark...."

    That's too complicated. Instead, you should do what Noach did. There wasn't enough room in the ark so he took cubs, calves, chicks etc. (Radal). Wait for this giant to lay some eggs and have them shipped. That would maintain the Noahide spirit at the museum!


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