Miscellanies. 197 



author of the Circular Scale, Dr. Warwick, aciaiowledges a pref- 

 erence for the hydrogen unit, on account of its giving whole num- 

 bers for tlie equivalents. The atomic weights given, approximate 

 very nearly to those of Dr. Thomson and Professor Brande. 



" In the employment of this scale it will be advisable to consider 

 the moveable circle as containing the weight of the object of en- 

 quiry. The fixed circle will contain the equivalent numbers. If 

 you wish to ascertain how much of any alkali, earth, or metal, will 

 saturate any given weight of acid, or vice versa, place the weight 

 you know under its equivalent, fasten the circle in its place, and un- 

 der the equivalent of the substance about which you are uncertain, 

 you will learn the weight required. For example 5 if you wish to 

 know how much carbonate of ammonia will saturate one hundred 

 grains of crystallized oxalic acid, place one hundred in the movea- 

 ble circle under seventy two, which is the equivalent of crystallized 

 oxalic acid, and then under thirty nine, which is the equivalent of 

 carbonate of ammonia, you will find fifty four and one fourth, which 

 is the quantity of the salt able to saturate one hundred parts of oxalic 

 acid." While the circle is thus placed, you may learn how much of 

 any other alkali, earth, or metal, will possess the same power, 

 by examining the numbers which are below the atomic weights of 

 those different substances. 



The author also proposes to ascertain by it how much of any sim- 

 ple substance is required to produce a given weight of any arti- 

 cle, into whose composition it enters, but this would be much easier 

 done by referring to the equivalent numbers, and calculating the result 

 on paper. The advantage which the scale possesses in the extreme 

 range of its numbers appears to be far more than counterbalanced by 

 the defective arrangement of the chemical substances. How far it 

 would compete with those which are straight, if the numbers were 

 arranged opposite to their equivalent numbers, is a question not yet 

 determined. I am however inclined to believe that the danger from 

 warping, in the circular scales, which are near fourteen inches in diam- 

 eter, would be much greater than in the WoUaston scale in common 

 use. One which should give the equivalent numbers of Sir H. Davy 

 and Berzelius is yet a desideratum. 



10. JVotice of a locality of Arragonite, near JVew Brunswick^ 

 (JY.J.) by J. Finch. — This mineral occurs in a quarry on the south 

 shore of Raritan River, one mile above New Brunswick. 



