In our last number, in a few words, we stated that Hon. John A. Dix had delivered a lecture before the New York Mecharics Institute, on a subject relating to the mechanical classes, a,nd that his lecture was not well attended. We rebuked our mechanics for their apathy and want of taste ; but the most keen rebuke which they have received comes from another quarter and in a different manner.mdash; The Hon. Ex-Senator, U. S., delivered a lecture inMetropolitan Hall, on the evening of the 6th inst., before the New York Historical Society, which embraces the most learned and distinguished gentlemen in our city. Instead of having a thin audience in that Hall, which is ten times larger than the rooms of the Institute, the hall was well filled and the audience very large. We are afraid that too many of our young mechanics go to hear songs and see mountebank exhibitions in preference to attending scientific lectures. Mechanics with families cannot attend lectures with the same convenience that persons of wealth can, but from their numbers in New York they ought to crowd the largest Hall in the city, whenever a lecture respecting their interests is delivered.