Volume 33 Number 44
                 Produced: Tue Sep  5  6:04:05 US/Eastern 2000

Subjects Discussed In This Issue: 

Electricity (2)
         [Rick Turkel, David Lloyd-Jones]
Eruv (3)
         [Daniel M Wells, Carl Singer, Joshua Hoffman]
Hat for Davening
         [Chaim Tabasky]
Hebrew & Roman Calendars
         [Eli Linas]
Inspiring intro to Judaism book
         [David Kaufmann]
Jewish Book for a Russian Bar Mitzvah Boy/Bat Mitzvah Girl
         [Judith Weil]
Lubavitch position on Eruvim
         [Alan Davidson]
Mila with Brit?
         [Yitzchak Scott-Thoennes]
Pi and the Yam Shel Shlomo
         [Mike Gerver]
Prayer with non-Jews - Correction
         [Yehoshua Kahan]
Some comments on Electricity
         [Russell Hendel]


From: Rick Turkel <rturkel@...>
Date: Fri, 1 Sep 2000 16:02:10 -0400 (EDT)
Subject: Re: Electricity

	In response to my posting on the above, in which I raised the
question of makeh bepatish (the "final hammer blow") in closing an
electrical circuit, our esteemed moderator, Avi Feldblum
<mljewish@...> wrote:

>I see very little fundimental difference between electron flow in a
>conductive path and fluid flow in a system of pipes. The electrons do
>not flow until I flip the switch on way, stop when I flip it the other
>way and restart when I flip it back to on. The water in my plumbing
>system does not flow till I turn the fluid switch (water faucet) on,
>flows till I turn it off, and then will flow again when I turn it back
>on. Both states (on and off) are stable states of the system. I find the
>arguement of Mache b'patish very weak.

	I beg to differ.  There is indeed a fundamental difference
between an electrical circuit and fluid flow in the plumbing system of
your home or workplace - when the electrical load is operating, the
former is a closed system, and only functions when there is no break in
the circuit.  Fluid flow in your plumbing, however, is an open system.
Take, for example, a sink or bathtub - the water leaves the faucet when
the tap is opened, and falls through the air and down the drain; closing
the drain has no effect whatsoever on the flow of water from the tap.
In contrast, any break in an electrical circuit will cause the electron
flow to cease.  The only possible way to use water in a closed system is
as a coolant or perhaps as a power supply for a turbine, where the water
remains within its closed system of pipes out of direct contact with the
"outside world."  Therefore, I believe that Avi has made a false analogy
between electrons flowing in a wire and water flowing in a pipe, and my
question still stands.

	Kol tuv, veshabbat shalom.

Rick Turkel      (___  _____  _  _  _  _  __     _  ___   _   _  _  ___
<rturkel@...>      )     |   |  \  )  |/  \ ein |navi| be|iro\__)    |
<rturkel@...>    /      |  _| __)/   | ___)    | ___|_  |  _(  \    |
Rich or poor, it's good to have money.    Ko rano | rani, u jamu pada.

From: David Lloyd-Jones <icomm5@...>
Date: Sat, 2 Sep 2000 02:14:20 -0400
Subject: Re: Electricity

Mike Gerver and Rick Turkel write:
<many thoughtful words, snipped>

My impression is that the use of electric lights came down in the
1880's, when closing a circuit showed an actual spark: real fire right
there before you eyes.

Today we operate at lower voltages, and in copper-to-copper contact we
use coatings and the shaping of the conductor to cut down on the
sparking, which in some circumstances might be a fire hazard.

Today we have transistor switches, in which there is no sparking.

This leaves, imho, two questions: 1.) Informed by scientific and
engineering fact, might the rabbis find differently about electricity?
And 2.) What's the best way of keeping shabbat?



From: Daniel M Wells <wells@...>
Date: Sun, 3 Sep 2000 21:26:32 +0300 (IDT)
Subject: Eruv

> From: Avi Feldblum <mljewish@...>
> So while I may disagree with my Chabad friends on the use of an eruv, as I
> will use the eruv, but focus more on making sure people understand that
> an eruv may not always be available, I respect their approach to the
> question.

Someone told me a long time ago that it's a mitzva to create an eruv,
but there is NO mitzva to have to carry in that eruv. In other words if
you have to bring a mohel's knife to shul or you just can't daven from
any other siddur but your own, then presumably being *self conscious* of
carrying in the eruv will prevent a midoraita issur of forgetting that
one is carrying especially when passing through the eruv confines.

All the more so when the eruv poles and Tzorech HaPetach wires are
fragile or in vandal inhabited areas and thus chances are that what was
a kosher eruv last night is now reshus harabim!

Also unless a solid wall *completely* surrounds the settlement or
neighborhood, then the kashrus of the eruv is based on a number of
'Kulot' which are often acceptable as a miminum to prevent non-frum
yiden doing a doraita aveira.


From: Carl Singer <CARLSINGER@...>
Date: Sun, 3 Sep 2000 22:36:53 EDT
Subject: Re: Eruv

<< I have heard similar claims that one should not use an eruv so their
 children understand the concept of the fact that there are many places
 where there are no eruvim. >>

Again, there are some communities that "take down" their eruv one week a
year partly as a "lesson"

Carl Singer

From: Joshua Hoffman <JoshHoff@...>
Date: Sun, 3 Sep 2000 13:08:07 EDT
Subject: Re: Eruv

<< This is analogous to the Lubavitcher reluctance to rely on eruvim,
  lest children go somewhere without an eruv and forget the prohibition
  against carrying on Shabbas.) >>

I was told by a friend who learned in Ner Yisroel that Rav Ruderman z'l
would not use the eiruv there becaues since that was where he almost
always was for Shabbos, he was afraid that he would forget about the
issur hotza'ah. Are there any Ner Yisroel graduates out there who know
anyhing about this?


From: Chaim Tabasky <tabaskc@...>
Date: Mon, 04 Sep 2000 13:35:17 +0200
Subject: Re: Hat for Davening

Around 1970, a friend of mine who attended Yeshvat Itri in JSLM asked
Rav Elyashiv if he had to ear a hat when dovening. This friend did not
normally wear a hat in the street, and didn't wear the hat to ask the
shealah. The Rav answered that he was not required to wear the
hat. Another friend at the yeshiva, incredulous at the answer went to
check it out. The second questioner wore his hat to Rav Elyashev. Rav
Elyashev told him he must wear a hat.  Though I didn't ask the question,
I believe the source of the info.

Chaim Tabasky


From: Eli Linas <linaseli@...>
Date: Sat, 02 Sep 2000 20:51:37 +0300
Subject: Re: Hebrew & Roman Calendars

Jonathan Baker <jjbaker@...> wrote:

>Eli Linas brings the gemara in Shabbos 75a that praises Israel for its
>knowledge of astronomy, which ability raises us beyond other nations...
>what primacy is Mr. Linas bemoaning?

I didn't know that I was "bemoaning" anything! I was merely responding
to Jay F Shachter <jay@...> statement: "I know of no article of
faith which requires Mr Wells to believe that we are better
mathematicians and astronomers than our neighbors." As I mentioned in my
original post, this is not an article of faith in the way the Rambam's
13 principles are, but it does count for something! Astronomy is far
from my area of expertise, but it seems to me that any statement in the
Gemara is one to be reckoned with, and instead of knocking Jewish
knowledge in this area, we should try to be matzdik it.

Eli Linas    


From: David Kaufmann <kaufmann@...>
Date: Sun, 3 Sep 2000 12:49:30 -0500
Subject: Re: Inspiring intro to Judaism book

While not an intro to Judaism book per se, Judaism Online: Confronting
Spirituality on the Internet (written by Shoshana Zakar and myself)
discusses many issues of current interest. It is the story of her
journey through the various branches, ending with an orthodox
conversion; as such, it confronts questions important to both would-be
converts and those journeying home. Available from amazon.com,
bookstores or the publisher, Jason Aronson.


From: Judith Weil <weildj@...>
Date: Mon, 04 Sep 2000 18:09:12 +0200
Subject: Re: Jewish Book for a Russian Bar Mitzvah Boy/Bat Mitzvah Girl

If you've read The Bamboo Cradle you may be interested to hear that it
is available in Russian.

Also I think (I'm not sure) that Voices in the Silence is available in

Feldheim's book store on Jerusalem's Strauss Street is a good place to
buy books of this type.

My own book - School for One - is also suitable for this age group, but
it is out of print and unless a bookshop has a copy hidden away
somewhere you are unlikely to find it at the moment.

Happy hunting,

Judith Weil


From: Alan Davidson <perzvi@...>
Date: Sun, 3 Sep 2000 16:42:57 -0400
Subject: Lubavitch position on Eruvim

It is not that Lubavitchers may come to rely on Eruvim but rather that
our not yet observant brethren (as well as non-Jewish onlookers) may
come to think there is no problem with carrying on shabbos because they
may or may know that an eruv exists.


From: Yitzchak Scott-Thoennes <sthoenna@...>
Date: Sun, 03 Sep 2000 15:41:54 -0700
Subject: Re: Mila with Brit?

Edward Ehrlich <eehrlich@...> wrote:
> I recently learned that someone born a Jew, who was circumcised, but not
> by a mohel, is required by Halakha to undergo "hatafa dam".
> Can someone explaining the reasoning behind this?  The mitzva of
> circumcision is placed upon a Jew's father.  So what is the halakhik
> necessity of a Jew circumcising himself?  Is this somehow connected with
> Avraham Avinu circumsing himself?

If I recall correctly, if the father doesn't perform the milah, the
beis din is obligated to do it.  If the beis din does not, the person
himself is obligated to do it (presumably upon reaching the age of bar

> Also, under what conditions must a previously circumcised Jew undergo
> "Hatafat dam"?  What happens if the the doctor who performed the
> circumsion is a Jew?

I wouldn't think that would be an issue.  I've heard that medical
circumcision here in the US is almost always done with the aid of a
clamp that prevents bleeding.  Perhaps there is also an issue of doing
it l'shem mitzvah [for the sake of the mitzvah]?  Either could still
be an issue with a Jew doing the circumcision.


From: Mike Gerver <Mike.Gerver@...>
Date: Sun, 3 Sep 2000 14:29:39 +0200 
Subject: Pi and the Yam Shel Shlomo

>From Zev Sero, in v33n39,

> The problem is with the gemara on Eruvin 15a, which insists that pi is
> *exactly* three, with not even a slight error.  It also insists that the
> Yam Shel Shlomo was perfectly round, which shoots down explanations that
> rely on odd shapes.  Tosafot points out the problem, but doesn't suggest
> an answer, and I haven't seen anyone else who even mentions it.

Saying that the Yam Shel Shlomo was perfectly round does not shoot down
ALL explanations that rely on odd shapes, only explanations that rely on
odd shapes in Euclidean geometry.  According to general relativity, if
you had a big enough mass inside the Yam Shel Shlomo, then the space
inside it would have positive curvature, and the ratio of circumference
to diameter would be less than pi.  For the right mass, the ratio would
be exactly 3.  I'm not going to calculate what mass is needed now-- it's
bad enough that I'm wasting the time to write this-- but I think it
would be greater than the mass of the earth but less than the mass of
Saturn.  This leads to a new problem: explaining why the Yam Shel
Shlomo, and the rest of the earth, didn't rapidly collapse into a black
hole.  But it DOES explain how the circumference could be exactly 3
times the diameter.

Disclaimer-- I'm not sure this explanation is original. I've discussed
it on several occasions with Zvi Siegel, and I don't remember who
thought of it first.

Mike Gerver
Raanana, Israel


From: Yehoshua Kahan <orotzfat@...>
Date: Sun, 3 Sep 2000 22:45:15 +0200
Subject: Prayer with non-Jews - Correction 

Oh, no!  Upon re-reading my post, I was aghast to see that I had written
"hand ten" instead of "hang ten".  Though I am now blissfully at home in
Israel, baruch Hashem (yes, I'll weigh in on that thread as well), I
certainly had no intention of forfeiting my Southern California,
15-minutes-from-the-beach credentials - the inevitable outcome of such a
gaff - so please register the correction with the appropriate

Former wannabe and now virtual surfer,

Yehoshua Kahan

P.S.  I have now seen several individuals attribute the song "Waters of
Babylon" to Don McLean.  Yes, that's the proper spelling, though his
house may be Spic 'n' Span (McClean) or he may be related to Shirley
(McClain - sp?).  Since I have a lingering affection for his music and
he was once wont to play concerts in Israel (oh, there I go again), I
thought I could apply to this discussion the the ma'amar Chazal: haomer
davar B"SHEM omro!


From: Russell Hendel <rhendel@...>
Date: Mon, 4 Sep 2000 13:03:24 -0400 (EDT)
Subject: RE: Some comments on Electricity

Two comments on the electricity discussion.

1) Rick Turkel brings the melacha of "completing an object"(Lit. the
finishing hammar blows).  However we must recall the law that eg while
it is prohibited to finish installation of a door in a house on shabbath
by closing the door (since that makes that house habitable),
nevertheless, it is completely permissable to open and close both doors
and windows on shabbath(even though when I eg open a window in the
winter I make the house unhabitable and therefore closing the window is
putting the finishing touches on the house and making it habitable).

The reason for this is that opening and closing windows and doors on
Shabbath is considered USAGE not CONSTRUCTION.

In a similar manner opening and closing circuits on Shabbath is
considered USAGE and is therefore not a violation of COMPLETING THE

2) Let us not forget throughout this dialogue Rabbi Broydes' point in an
article he wrote in the Journal of Comtemporary Halachah, that EVEN if
there is no foundation for prohibiting electricity nevertheless since
Gedolim have already prohibited it it is established as "the way of
Israel" and we should continue abstaining (I guess until enough Gedolim
undo the former Psaks)

Russell Jay Hendel; phd AsA
Dept of Math; Towson Univ
Moderator Rashi is Simple


End of Volume 33 Issue 44