176 



Scientific Intelligence, — Mineralogy. 



For Towns. 



DRAFT PLANS. 



Inches to Mile. 



20 



24 



40 



60 



80 



96 



105| 



120 



132 



240 



264 



Replies in 

























favour of the above 



1 



4 



2 



29 



6 



1 



1 



65 



1 



2 



2 



Scale. 































ENGRAVED. 







Inches 

 to Mile. 



1 



6 



10 



12 



20 



24 



30 



40 



48 



52f 



60 



120 



132 



Re- 





























plies in 





























favour 

 of the 



1 



1 



1 



2 



1 



3 



1 



3 



1 



1 



67 



10 



2 



above 





























Scale. 





























N.B. — Fifteen have not mentioned the Scale, but it appears from the notes 

 appended, that they are all in favour of a larger Scale than the Six-Inch. 



Note. — Replies received from four County Towns, three in favour of tho 

 6-inch Scale and one in favour of the 1-inch Scale. 



SCIENTIFIC INTELLIGENCE. 



MINERALOGY. 



1. On the Formation of Crystallized Minerals. By Aug. Frever- 

 mann. (Annalen der Chemie 9 1853, vol. lxxxviii., p. 120.) — A se- 

 ries of experiments with which I have been lately engaged seem to 

 throw some light on the formation of crystallized minerals from 

 aqueous solutions. I started upon a conviction that crystals found 

 in geodes could have been formed neither by evaporation nor by re- 

 frigeration of saturated solutions, and I think I have suceeded in dis- 

 covering the mode of formation of such minerals. The method is 

 equally applicable to very soluble or slightly soluble bodies, and 

 admits of an infinite variety of modifications in its mechanism. Its 

 principle is nothing else than a gradual alteration of the affinity of 

 the solvent to the dissolved body, so that the precipitation occurs 

 very slowly. The gradual change of chemical force is obtained by 

 the diffusion of one liquid into another, such as in mixing produce 

 a solid precipitate. The arrangement of the apparatus is the same 

 as in Graham's experiments. Powdered chromate of potash was 

 placed in the bottom of a long glass cylinder, and powdered nitrate 

 of lead in the bottom of another ; both were then filled with water, 



