To: Rabbi Mordechai Halperin, M.D.
Dear Rabbi Halperin,
I was surprised to learn recently that John Dalton is credited with giving the first substantive paper on color blindness — and this was only 220 years ago. In consideration of the importance of being able to make certain color distinctions in Torah life, it may be that this issue was noticed in the Torah world long before Dalton.
A. S. Adler
PS. You may remember Prof. Shaul Adler — who would have been the tenth in a line of rabbis from father to son– a grandson of my great -grandparents — who lived in Kletsk
PPS. I was drawn to this issue by the unusual comment by Rashi — both in Truma and at tsitsis — that techelis is Yarok.
While trying to understand this , I came upon the well known Yerushalmi Brochos 2.1 on Tchelis:
שהתכלת דומה לים והים דומה לעשבים ועשבים דומין לרקיע ורקיע דומה לכסא הכבוד
This suggests that תכלת is associated with green herbage. The Vilna Gaon emends the text, omitting ‘… herbage…’ making it like the statement in the Bavli, Menuchos 43: שהתכלת דומה לים וים דומה לרקיע ורקיע לכסא הכבוד .
However, our sages of the Yerushalmi in Tiberias, by the Sea of Galilee, would’ve only had to look NE to the green covered mountains across the sea – to see the sea, herbage & sky blended together in that order – & all of them blue. The blueness of the herbage on the distant mountain sides is caused by the same phenomena that make the sky blue – the scattering of the light of the sun and sky by the molecules of the air between the viewer and the greenery– where blue light is scattered nearly ten times as much as red. [See A Practical Analytic Model for Daylight, A. J. Preetham, ‘99, Proc of the 26th An. Conf. on Computer Graphics and inter. Tech.. P. 91-100] http://www.cs.utah.edu/~shirley/papers/sunsky/sunsky.pdf
Here is a link to a photo that shows this — on the left hand side of the frame:
SEA OF GALILEE LOOKING NE FRM TIBERIAS- JUDGING BY SHADOWS ~4PM- SHOWING THE BLUING OF THE VEGETATION ON THE M’NTAINS NR THE NE SHORE ~15-18KM AWAY- & THE SIMILARITY OF THE COLORS OF SEA, HERBAGE [BETWEEN ARROWS] & SKY.
LARGER PHOTO BY RAZ MACHLEV, PANORAMIOhttp://www.panoramio.com/photo/42059990
From a sefer that I am writing.
There are several pieces in this sefer I think you would like to see and would be glad to send you the latest pdf with indications of what would probably be most interesting to you — from the Torah and bio-ethics perspective — particularly a chapter concerning the use of human bodies in anatomical education and the extremely unfortunate experience of AECOM and another on Chazal, bloodletting in pneumonia and the work of Dietl.
Dear Rabbi Adler
Thank you for contacting us with this fascinating question – in fact here at Machon Schlesinger we have done some research into the issue of color blindness in Chazal and Halachic implications thereof. Would it be Ok to respond in Hebrew?
Also – we would very much appreciate any materials you send us (via the same email firstname.lastname@example.org)