# What are these three types of Amos?

I'm not one to usually go to Google itself to learn about Judaism, but I feel that the circumstances around how I discovered this is really intriguing...

Google Maps has a nice little feature that allows you to measure distance on the map using a virtual ruler. To activate it, you will need to enable it in Maps Labs (available by clicking the "settings" icon in the upper-right corner). Then click on the little ruler-icon on the lower left corner of the map.

Once you have it running, you will be able to measure the distance between two points on the map. By default, the measurement is taken in meters. You can select "english" units or "metric units" OR you can click "I'm feeling geeky", which will let you take the measurements in anything from American Football Fields to Light-years.

But what struck me as odd is that Google listed three additional methods of measurement:

• Jewish 1st Temple cubit
• Jewish 2nd Temple cubit
• Jewish 2nd Temple sacred cubit

Doing some quick calculations Google gives these in modern-terms as (approximately):

• Jewish 1st Temple cubit = 1.405 ft.
• Jewish 2nd Temple cubit = 1.458 ft.
• Jewish 2nd Temple sacred cubit = 1.436 ft.

As far as I can recall, I only know of one type of cubit (a.k.a. Amah). So what is the origin of these three types of cubits?

And a screenshot, for your convenience:

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Google paskins like A"H Noeh :), though the Amah is a bit small even for R' Noeh. – Shmuel Brin Oct 19 '11 at 2:11
@Shmuel: nah, all of them are too short even for his opinion - he makes an amah 48 cm; these vary from 42.8 to 44.5 cm. – Alex Oct 19 '11 at 14:10

There was a

• small amah (5 tefachim/amah)
• medium amah (6 tefachim/amah)
• 2 large amahs (6t/a + half a finger-breath & 6t/a + a whole finger)

According to R. Yehudah, the temple building was measured by the 6t/amah and the vessels are all measured by the 5t/amah.

According to R. Meir, the 6 tefach amah was used everywhere except the gold alter, and the copper alter's horns, sovev and base.

There were two additional larger cubits established in Shushan. One, a half a finger-breath longer than the 6 tefach amah, and a second that was a finger-breath longer. So that workers don't accidentally return less material than they removed from the treasury - eg. workers remove gold with the medium amah, and return gold measured with the larger amah.

-Menachos 97a-98a

(I don't know how accurate Google's conversions are, and I don't know about attributing them to specific temples)

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