19. How many children are there in all our Sabbath-schools? _Answer._ If the question refers to the United States, I think we may safely say that now we have, in Sabbath-schools, about four million children and youth, with about four hundred thousand teachers. A quarter of a century ago or so, the numbers were estimated at two million five hundred thousand, but this was when the great Western States were in their comparative infancy. The number rapidly increased to three millions, and then to three million five hundred thousand, and now our returns and estimates reach four millions. Great Britain has about the same number, both of teachers and scholars; but we do not think all other countries can raise the full number of Sabbath-school children quite up to _ten millions_, or the number of Sabbath-school teachers to a grand army of _one million_ strong. The census of 1860 gave the number of persons in the United States, between the ages of five and sixteen, at nine millions (or only a few thousands less). As a consequence, we have the great aggregate of _five millions_! of unreached and uncared-for children and youth in our land. What an immense and hopeful missionary field here lies open at our doors! There is scarcely a State in our whole Union or a city which can truly report _one-half_ of her children in any kind of a Sabbath-school on any given day. And yet some of our great States are working very energetically and systematically. Witness the State of Illinois, which has organized every one of its one hundred and two counties during the past two or three years, by the voluntary and Sunday-school missionary labors of its Sunday-School Association, aided by other agencies. What this State has done, other States, if they will, can do, and the immense work before us, when systematically undertaken, is by no means a hopeless task. _The Answer Box._