AMERICAN INSTITUTE. 391 



net wticli sustained tlie weight oi fifteen thousand pminds, which, at the 

 distance of three or four inches, was only four or five founds. That the 

 cost of half a horse power per day was nearly £5 ($25). 



Mr. Siemens has said the cost, compared with steam, was 300 to 1. 



Mr. Newton said that a rotary was made 20 years ago which showed 

 some power. 



Mr. Henry Revely states in a letter, that Mr. Palmer, of No. 122 New- 

 gate street, (Horn & Thornthwaite's,) about 1840, made for him a polyzo- 

 nal piston rod, armed with many keepers, passing up and down between an 

 indefinite number of stages of powerful horse-shoe magnets, combined with 

 a new mode of instantaneously making and breaking any number of circuits 

 by means of cranks and jointed levers. Palmer found that only Q\ per 

 cent, of the holding power of the electro-magnet was available as motive 

 power at the distance of the thickness of letter paper — or that a magnet of 

 100 lbs. holding power would only pull 16 lbs. at that distance. 



f From the same Journal.] 



PUDDLED STEEL. 



Mr. Barlow states, that in addition to that, quality of which the tensile 

 strength is stated at 160,000 lbs. per inch, and in one sample 173,817 lbs., 

 other samples, representing a different quality of the material, exhibited a 

 strength of 112,000 lbs. per inch, or about twice the strength of iron. 



A girder of 289 tons would possess the same effective strength as the 

 Menai tube, which weighs 1,553 tons. This shows the great importance 

 of obtaining more accurate knowledge of this new material, and whether 

 the strength of puddled steel can be uniformly depended on, or what vari- 

 ations it is liable to. 



Applied to roads, although capable of great duration, steel rails will not 

 last forever ; and when worn out, are more difficult than iron to repair. 



The question is made whether oil is not a better /?^eZ than coal for steam 

 ■engines. 



Wood is talked of for bearings of shafts, especially propellers, as with 

 certain pressures it is many times more durable than metal. 



Mr. Johnson. — I and my partner, Mr. Wolcott, made an electro-mag- 

 netic machine, many years ago ; rotating and fixed magnets ; the power 

 exerted tangentially. Time is an element in this power, for iron is not 

 capable of receiving the magnetic power instantaneously, but slowly. The 

 magnets are, therefore, not charged suddenly, as is generally believed. 



Mr. Seeley. — The softest iron is soonest charged ; and that is so with the 

 coils. I think that there is no hope for success with the electro machine, 

 unless a material greatly cheaper than zinc be substituted. 



Mr. Johnson. — I suggest for the reflection of members, that electricity 

 may be available without magnetism, for motive power, 



Mr. Leonard adverted to Paine's electro-magnetic engine, exhibited in 

 in this repository some time ago, as exhibiting, by dynamometer, about 

 one-seventh of one horse. 



