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Scientific Intelligence. 



railway bars, which from their softness and lamellar texture soon become 

 destroyed. The cost of semi-steel will be a fraction less than iron, be- 

 cause the loss of metal that takes place by oxydation in the converting" 

 vessel is about 2-J per cent, less than it is with iron ; but, it is a little 

 more difficult to roll, its cost per ton may fairly be considered to be the 

 same as iron ; but, as its tensile strength is some thirty or forty per cent, 

 greater than bar-iron, it follows that for most purposes a much less weight 

 of metal may be used, so that, taken in that way, the semi-steel will form 

 a much cheaper metal than any that we are at present acquainted with. 



In conclusion, allow me to observe that the facts which I have had the 

 honor of bringing before the meeting have not been elicited from mere 

 laboratory experiments, but have been the result of working on a scale 

 nearly twice as great as is pursued in our largest iron works, the experi- 

 mental apparatus doing seven cwt. in thirty minutes, while the ordinary 

 puddling furnace makes only 4-J- cwt. in two hours, which is made into 

 six separate balls, while the ingots or blooms are smooth even prisms, 

 ten inches square by thirty inches in length, weighing about equal to ten 

 ordinary puddle balls." 



12. On some Dichromatic Phenomena among Solutions, and the means 

 of representing them ; by Dr. Gladstone, (Proc. Brit. Assoc. August, 

 1856; Ath. No. 1505.) — This paper was an extension of Sir John Her- 

 schel's observations on dichromatism, that property whereby certain 

 bodies appear of a different color according to the quantity seen through. 

 It depends generally on the less rapid absorption of the red ray as it pen- 

 etrates a substance. A dichromatic solution was examined by placing it 

 in a wedge-shaped glass-trough, held in such a position that a slit in the 

 window-shutter was seen traversing the varying thicknesses of the liquid. 

 The diversely colored line of light thus produced was analyzed by a prism ; 

 and the resulting spectrum was represented in a diagram by means of 

 colored chalks on black paper, the true position of the apparent colors 

 being determined by the fixed lines of the spectrum. In this way the 

 citrate and comenamate of iron, sulphate of indigo, litmus in various con- 

 ditions, cochineal, and chromium, and cobalt salts were examined and 

 represented. Among the more notable results were the following : — A 

 base, such as chromic oxyd, produces very nearly the same spectral im- 

 age with whatever acid it may be combined, although the salts may ap- 

 pear very different in color to the unaided eye. Citrate of iron appears 

 green, brown, or red, according to the quantity seen through. It transmits 

 the red ray most easily, then the orange, then the green, which covers the 

 space usually occupied by the yellow ; it cut off entirely the more refran- 

 gible half of the spectrum. Neutral litmus appears blue or red, according 

 to the strength or depth of the solution. Alkalies cause a great develop- 

 ment of the blue ray ; acids cause a like increase of the orange, while 

 the minimum of luminosity is altered to a position much nearer the blue. 

 Boracic acid causes a development of the .violet. Alkaline litmus was ex- 

 hibited so strong that it appeared red, and slightly acid litmus so dilute 

 that it looked bluish purple ; indeed, on account of the easy transmissi- 

 bility of the orange ray through an acid solution, the apparent paradox 

 was maintained that a large amount of alkaline litmus is of a purer red 

 than acid litmus itself. Another kind of dichromatism was examined, 



