I have heard a legend. (I use the word legend, because the veracity of this story has been questioned, as we have no definitive sources that support it.) The story is told that the curators of a Russian museum had obtained a precious stone/mineral that had unique, remarkable powers. The Russian scientists could not fathom the secret of this stone. They did not even know what kind of stone it was. They decided that since German scientists were more advanced technologically, they would send them the stone. The German scientists were, likewise, stupefied by this stone. Among the group of scientists was Moses Mendelssohn, the founder of secular Judaism, who advised that they send the stone back to Eastern Europe to Vilna, the home of the Gaon of Vilna. He would tell them the nature of this stone. Mendelssohn’s intentions were far from noble. He assumed that if he could not discern the nature of the stone, neither could the Gaon. This would lower the Gaon’s esteem in the eyes of his numerous followers throughout the observant Jewish community.
When the two emissaries from Germany arrived in the humble home of the Gaon, he asked them to place the stone on the table. The Gaon then asked his shamash, aide, to bring him a glass of water in which he dropped the stone. As soon as he did this – the water in the glass evaporated, literally disappeared. (Another variation of the story contends that the water on each side of the stone split.) When the Gaon saw the look of incredulity on the faces of the German scientists, he explained that the stone was a sapphire. When water comes in contact with a sapphire, the two elements which comprise the sapphire – hydrogen and oxygen – separate, and the sapphire reverts back to its original elements. In other words, the stone becomes hydrogen and oxygen.
The dumbfounded scientists had a renewed admiration for the genius of the famous Rabbi of Vilna, and they reiterated this over and over when they returned. We would expect Mendelssohn to have been upset that his diabolical plan to besmirch the gaon hador, preeminent Torah giant of the generation, in particular, and, by extension, Orthodox Judaism in general, but we would be wrong. Indeed, Mendelssohn used this wondrous stone and its remarkable properties to undermine and vilify the Torah from which he had separated himself.
He claimed that we can now understand how Moshe Rabbeinu had the ability to split the Red Sea with nothing more than his staff. Indeed, he explained, this “miracle” was actually a natural scientific phenomenon. Moshe’s staff was composed of sapphire (according to Chazal). Thus, when Moshe placed his wondrous staff in the water, it naturally split. The alchemic properties of the sapphire were the natural cause of the Splitting of the Red Sea – not the miraculous intervention of Hashem!
Word of Mendelssohn’s heresy came back to the Gaon, who exclaimed “Apikores! Heretic!” The Torah explicitly writes that Hashem instructed Moshe: Hareim es ha’mateh, “Lift up your staff”; u’neteih es yadcha al ha’yam, “and stretch out your hand on the sea.” Hareim means lift the staff; it had never touched the water. Natei es yaddcha, “stretch out your hand,” over the sea. Nothing, absolutely nothing, came in physical contact with the water, rendering this a supernatural miracle.
Furthermore, in the Pirush HaRosh Al HaTorah, the Rosh writes, “I heard from my saintly father that Krias Yam Suf, the Splitting of the Red Sea, was not effected through the medium of Moshe’s staff. The Heavenly Angels denigrated Moshe, saying, “Indeed, if any one of us would have access to Moshe’s remarkable staff, we, too, could split the sea.” Hashem “countered” by telling Moshe to raise up the staff, so it should not touch the water: “spread your hand over the water.” Krias Yam Suf was pure miracle, which catalyzed the belief of the Jewish People in Hashem.