Magen Dawid

Picture is copied fron the Jewish Encyclopedia and it shows the logo of the first Jewish organisation who adopted the Star of David as its logo in 1873.
I tried to find out what the Jewish Encyclopedia (1901-1906) has to say about the Star of David but searching for these words or for Magen David yielded nothing, because the article was under the title MAGEN DAWID. Later I found out that I could have found the article by searching for Shield of David.
Anyhow, the article was written by Joseph Jacobs and Ludwig Blau long before the Star of David found its central place in the Israeli flag. It was fascinating to reveal how fresh and informative is the article even today.

It starts by describing the form of the emblem:

The hexagram formed by the combination of two equilateral triangles;

Then goes on to describe its usages:

used as the symbol of Judaism. It is placed upon synagogues, sacred vessels, and the like… In the synagogues, perhaps, it took the place of the mezuzah

Close to the end of the article it refers to the source of the name:

and the name "shield of David" may have been given it in virtue of its protective powers.

It refers to the adoption of the shield of David as a Jewish national emblem:

1. Adopted as a device by the American Jewish Publication Society in 1873
2. the Zionist Congress of Basel
3. "Die Welt" (Vienna), the official organ of Zionism.
4. By other bodies.
5. The Chebra Kaddisha of the Jewish community of Johannesburg, South Africa, calls itself "Cebra Kaddisha zum Rothen Magen David," following the designation of the "red cross" societies.

The main part of the article is dedicated to the history of the Magen Dawid:
1. Introduction
2. Archeological artifact 
3. Literary sources
4. Cabala
5. Charles IV.
6. Usage by other cultures:
a. Hindus
b. Christians
7. The hexagram’s relation to the pentagram
8. Bibliography