ELECTRICAL LABORATORY FOR BEGINNERS. By GEO. M. HOPKINS. It is only when theory and practice, study and experiment, go hand in hand that any true progress is made in the sciences. A head full of theory is of little value without practice, and although the student may apply himself with all his energies for years, his time will, to a great extent, have been spent in vain, unless he by experiment rivets... more...

Nitro-Glycerin. Professor Doremus of this city was called as a witness at the inquest upon the bodies of the unfortunate persons killed by the recent explosion at Bergen, N.J. The Professor having previously analyzed some of the explosive mixture, testified as follows:—"I have subjected it to chemical analysis, and find it to correspond to the formula C_{6}, H_{3}, O_{3}, and NO_{5}; it is well... more...

GUN PRACTICE IN THE FRENCH NAVY. The gunners of the French fleet are possessed of a skill which is recognized by all the maritime powers, and these picked men proved this at the siege of Paris, where they made themselves illustrious, not only by their courage and their coolness, but also by the accuracy of their firing. Nothing is neglected, moreover, to keep up the precision of hand and eye that... more...

Recently, a party consisting of engineers and employes of the Missouri River Improvement Commission began an exploration of one of the mounds, a work of a prehistoric race, situated on the bluff, which overlooks the Missouri River from an elevation of one hundred and fifty feet, located about six miles below Jefferson City. This mound is one of about twenty embraced in a circle one quarter of a mile in... more...

THE GREAT EQUATORIAL OF THE PARIS OBSERVATORY. The great instrument which has just completed the installation of our national observatory is constructed upon the same principle as the elbowed equatorial, 11 in. in diameter, established in 1882, according to the ingenious arrangement devised as long ago as 1872, by Mr. Loewy, assistant director of the Paris Observatory. We shall here recall the fact... more...

THE NEW LABOR EXCHANGE, PARIS. The new Labor Exchange is soon to be inaugurated. We give herewith a view of the entrance facade of the meeting hall. The buildings, which are the work of Mr Bouvard, architect, of the city of Paris, are comprised within the block of houses whose sharp angle forms upon Place de la Republique, the intersection of Boulevard Magenta and Bondy street. One of the entrances of... more...

THE STUDY OF MANKIND. Professor Max Muller, who presided over the Anthropological Section of the British Association, said that if one tried to recall what anthropology was in 1847, and then considered what it was now, its progress seemed most marvelous. These last fifty years had been an age of discovery in Africa, Central Asia, America, Polynesia, and Australia, such as could hardly be matched in any... more...

I have the honor this evening of addressing a few remarks to you upon the subject of influence machines, and the manner in which I propose to treat the subject is to state as shortly as possible, first, the historical portion, and afterward to point out the prominent characteristics of the later and the more commonly known machines. The diagrams upon the screen will assist the eye to the general form... more...

TURPENTINE AND ITS PRODUCTS. By Edward Davies, F.C.S., F.I.C. In treating this subject it is necessary to limit it within comparatively narrow bounds, for bodies of the turpentine class are exceedingly numerous and not well understood. In this definite class turpentine means the exudation from various trees of the natural order Coniferæ, consisting of a hydrocarbon, CH, and a resin. The constitution... more...

STEAM ENGINE VALVES. By THOMAS HAWLEY. In considering the slide valve in its simple form with or without lap, we find there are certain limitations to its use as a valve that would give the best results. The limitation of most importance is that its construction will not allow of the proper cut off to obtain all the benefits of expansion without hindering the perfect action of the valve in other... more...