R. Hayyim Hirschenson, Jacob Mordecai's second son, was born in Safed. In 1864 he went with his father to Jerusalem. In addition to studying Torah, he applied himself to secular studies, and as a result he too was persecuted by zealots. He also worked for Zionism; he supported Eliezer Ben-Yehuda in his effort to revive spoken Hebrew and was one of the founders of the Safah Berurah ("Plain Language") society in Jerusalem. From 1885 to 1889 he edited and published a monthly for Jewish scholarship entitled Ha-Misderonah. In 1892/93 he published in Jerusalem - together with his wife Eve and his brother Isaac - a Yiddish paper, Beit Ya'akov, as a supplement to the Ha-Zevi of Ben-Yehuda. In 1904 he went to the U.S., where he was appointed rabbi of the four communities of Hoboken, New Jersey, and died there. Hayyim wrote many books on Jewish subjects, including: Ateret Hakhamim (1874), on the relationship between the views of scientists and those of the talmudic aggadists; Yamim mi-Kedem (1908), on biblical chronology; Malki ba-Kodesh (6 parts, 1919–28), on the laws which should govern a Jewish state according to the Torah. He was the father of Tamar, wife of David de Sola Pool, and Tehilla Lichtenstein head of the Jewish Science movement.

חלק א: ברייתא דרבי ישמעאל בכלל ... קל וחומר. תרפ"ט. פורטריט, [8], [3]-302, [2]; 18 עמ', [1] פאקסימיל. חלק א: 18 עמ': חלק אנגלי. כולל: דברי הערכה על המחבר ומבוא באנגלית, מאת ד"ר מוריס ליכטנשטיין, חתנו. חלק ב(-ד): בג"ש [בגזירה שווה], היקש, ובנין אב. תרצ"א. [10], [3]-224; 314, [3] עמ'. חלק ב(-ד): עמ' [1]-272 מן הספירה השנייה, עם שער מיוחד: חלק שלישי. בכללי ופרטי ובו שבעה ערכין. בשולי השער: תר"ץ. חלק ב(-ד):עמ' [273]-314, עם שער מיוחד: חלק רביעי. בדבר הלמוד מענינו, ומסופו. ובהסתירה, הכחשה, וההכרעה. ובו שלשה ערכין. בשולי השער: בר"ץ