78 Progress of Invention. 



electro-magnetists much ground for sanguine expectations. In 

 cases, however, in which only small power is required, and the cost 

 of its production is but a secondary consideration, while from the 

 intermittent nature of the work to be done, and other circumstances, 

 a steam-engine would be out of the question, electro- magnetism may 

 be applicable. But, considering the complication and cost of any of 

 the electro-magnetic engines yet invented, it is to be feared that the 

 period at which electro-magnetism will be utilized, even to this limited 

 extent, is still distant. 



Pointing of Pins and Needles by Electricity. — The 

 pointing of pins and needles is not only a troublesome, but, notwith- 

 standing all the improvements that have been made, an exceedingly 

 unhealthy operation. The fine metallic dust which is produced 

 enters the lungs, and causes disease, which, sooner or later — gene- 

 rally very soon — proves fatal. There is, however, reason to believe 

 that the old and objectionable process will soon be superseded by a 

 new, a simple, and a harmless one. The latter was supposed to 

 have been recently discovered at Lausanne by M. Canderay, a tele- 

 graph engineer ; but a correspondent of Les Mondes, in the number 

 for December 29, shows that he had published an account of the 

 method so long ago as 18G0 ; he admits, however, that its application 

 to the pointing of pins and needles is a happy and recent idea. The 

 pins, etc., to be pointed are placed close together in a bundle. The 

 latter is to be held perpendicularly, and its upper end having been 

 brought in contact with the positive pole of a Bunsen battery con- 

 sisting of one or two elements, it is to be immersed in acidulated 

 water contained in a vessel, through the bottom of which the nega- 

 tive pole of the battery has been passed up ; the lower end of the 

 bundle and the upper end of the negative pole being kept within a 

 very short distance of each other. In a few minutes, the number 

 being greater or less, according to the nature and concentration of 

 the acid, the nature and thickness of the wires, and the intensity of 

 the current, the ends of the wires next to the negative pole of the 

 battery will have been pointed, the sharpness and form of the points 

 depending on the distance between them and the negative pole. 

 One hundred wires have been pointed in this way, in a few minutes, 

 with a Bunsen battery, consisting of but a single element. Hence, 

 from the smallness of the electric power, and the shortness of the 

 time required, the process promises to be very economical. Sulphuric 

 acid answers best for iron or steel ; nitric acid for copper or brass. 

 Our readers can easily make an experiment, illustrating this process 

 by immersing the wire constituting the positive pole of a small bat- 

 tery in dilute acid contained in a glass tube, the lower end of which 

 has been closed with a cork, through which the negative pole of the 

 battery has been passed up. The poles are to be kept for a few 

 minutes very near each other within the fluid. 



Simplification of the Common Pump. — A modification of 

 the ordinary suction pump, as it is called, has lately been invented 

 and patented in Prance, which seems, for many purposes at least, to 

 recommend itself strongly by its simplicity, and other good qualities. 

 The common pump consists, as is well known, of a barrel, a piston, 



