Workmen and their Tools. A good test of a good workman one of the best apart from his workmanship is his care of tools. If he leaves a worn out or dilapidated tool in its imperfect state until he gets time to put it into shape, he he lacks in the organ of order, which should be the shop's, as Pope says it is Heaven'd first law. But if he repairs the tool soon as it is injured, whether wanted for use at the time or not, he can be depended upon. A carpenter may be known by his chips ; but a workman at any business may be known by /the state of his tools. Effect of Trees on Climate. The dryness of the Egyptian climate is such that rain is unknown in Upper Egypt, and in olden time it never rained of tener than five or six days in a year on the Nile delta. The viceroy, Mehemed Ali, caused twenty millions of trees to be planted on this delta; these have now attained their full size, and the number of rainy days has increased to forty annually. Such is the power which man can exert over nature in the matter of varying meteorological conditions. A "New England Mechanics' and Art Association" has been organized at Boston, of which ex-Governor Bullock, of Worcester, Mass., is President. The circular before us, which we are requested to notice, does not give any information respecting the purposes of the association, but we should judge, from the number and character of the gentlemen who are its sponsors, that a good deal may be expected from it. Monument to Humboldt. It is proposed by a number of our citizens to commemorate the centennial birthday of Humboldt by the erection of a monument to his memory, in the Central Park, at a cost of $2,500. Subscriptions are solicited in behalf of this commendable undertaking by a committee of well-known gentlemen, of which Christian E. Detmold, of this city, is the treasurer. Improved Printing Mechanism. One of Bullock's patent presses, at the Government printing office, Washington, attended by two persons, does the entire work which recently required for its execution no less than eighteen of the Adams presses, coupled with the labor of twenty persons. The steam power used to drive the Bullock press is not much greater than that needed for one of the old presses. Ink from Elder. In a receipt for making ink from elder, on page 180, an incongruity has crept in. The sentence reading "add to 12-J parts of the filtered juice one ounce of sulphate of iron," etc., should read, add to 12 ounces of the filtered juice one ounce of sulphate of iron, etc. A new chemical laboratory, just completed at the University of Leipsic, is the largest and most perfect, in regard to its internal arrangements, of any in Germany. The corner stone was laid in August, 1867, and the building was opened to students in last November. There are only seventy-five miles of rail remaining to be laid on the Pacific Railroad, and it is expected that a locomotive will run through to San Francisco early in the summer. The highest point on the road is 7,500 feet above the sea. We are out of some of the back numbers of this volume. Subscribers who write for missing numbers will always be supplied wh'en it is possible for us to do so. We make this statement to answer several applications. We are indebted to General H. A. Barnum, of Syracuse, N. Y.., for a copy of Report of the Inspectors of State Prisons, for 1869, for which he will please accept our acknowledgments.