On Crystallography, 143 



greatly under the general average of expense ; so that, upon 

 the whole scheme, (embracing an inland navigation of from 

 CO to 70 milesj) taking into view its extensive connexions, 

 tiiere appears a fair prospect of ample remuneration for the 

 adventurers. Thomas Telford. 



Stamford, 8th Jan. 1810. 



In consequence of the foregoing Report, it was resolved^ 

 at a meeting of the committee held at Stamford on the 8th 

 of January, 1610,— -That it appears to this committee to 

 be impracticable to go to parliameni in the now ensuing 

 Session for the sanction of the legislature to the plan which 

 Mr. Telford has proposed, in.Wnuch as the necessary sur* 

 veys cannot be in due time prepared, nor the notices given> 

 nor the plans delivered, which are recjuired preparatory to 

 the mtroduction of navigation bills into parliament : but 

 that Mr. Telford be directed to take the steps proposed in 

 his report, and that every other proper measure be pursued 

 for the introduction of the bill into parliament in the session 

 following. 



XXI. On Crystallo^rap/iy, By M, Hauy. Translated 

 from the last Paris Edition of his Traite de Mineralogie. 



[Continued from vol. xxxlv. p. 466.] 



If these ridges were subject to a different law, which gave 

 rise, for example, to sublractions of two ranges, the sign 



'i L'-O 



would become De E P B ^. According to this it has been 



considered as settled, that the decrements represented by a 

 large letter accompanied by any cypher would not implicitly 

 contain similar decrements represented by the small letter 

 of the same kind, or vice versa, i. e. for example, that 

 B would not implicitly contain by or, vice versa, that when the 



second letter would not enter into the expression of the sign 

 with a difterent cypher, we should not use the same cypher 

 accompanied by a zero. In the first case each of the two 

 letters expresses a decrement which is peculiar to the ridge 

 or to the angle which it indicates ; in the second^ that which 

 is affected T)y a zero shows that the angle or the edge to 

 which it exclusively relates undergoes no decrement. Thus 



eEPBZ', B expresses a decrement by one 



jange, which only takes place on the ridges contiguous to 

 the upper summit A (fig. 73) ; b indicates a decrement by 



Vol. 35. No. 142, Feb, 1810. K two 



