Robert Sietsema attempts to delve into the history of Bosco Chocolate Syrup and comes up rather empty-handed. Strangely, he ignores the matter of one of life’s long-standing but endangered pleasures, Bosco chocolate soda from the fountain. You can still get the stuff at 2nd Avenue Deli, but now that Gramercy’s Burger Joint has closed, where else can you find it? 67 Burger tells us it stopped serving Bosco a few months ago because it wasn’t popular, which just boggles our mind. Nobody likes a carbonated chocolate beverage? Really? Anyone know a random slice joint or somesuch that’s keeping the flame alive?