Intelligence and Miscellanies. 371 



10. Dr. Wollaston'^s scale of chemical equivalents. — We 

 have already mentioned that an improved edition of this 

 very useful instrument has been published in this country by 

 Professors Beck and Henry of the Rensselaer school : it ap- 

 pears that still another edition is about appearing at Middle- 

 town, Conn. 



Messrs. Hedge ^- Co. of that place,have just commenced 

 the manufacture of Wollaston's Scales. The one before us, 

 says a writer in the American Sentinel, is the most finished 

 specimen of workmanship of the kind we have ever yet seen ; 

 and the first attempt in box wood, to our knowledge, in this 

 country. The scale is>21 inches in length, by 3 and 2-lOths 

 in breadth. 



The graduation is done by machinery, and is executed with 

 a degree of beauty and accuracy we have never seen equal- 

 led by any thing of the kind. 



Those who are acquainted with the use of rules, know 

 how difficult it is to obtain such as are accurate. Mr. Hedge, 

 by means of his machinery, is enabled to make the best rules 

 in this country, and they are, in consequence, highly esteem- 

 ed by all competent judges. 



Great care has been taken in the plan of arrangement of 

 the chemical substances. The elementary bodies, metals, 

 and metallic oxides, are arranged on one side of the slide, 

 by themselves — the names of the metals are printed in larger 

 type, which adds not only to the beauty of the scale, but 

 renders it much easier to find their respective places. 



With regard to the representative numbers of the chemi- 

 cal substances, the greatest care has been taken in consult- 

 ing the latest tables of Drs. Henry, Thomson, and others so 

 as to correct the errors of former tables. 



The scale, thus improved, was made at the suggestion and 

 under the superintendence of Doct. J. Barratt. 



Uniformity in the scales can be depended upon because 

 the graduation of the line of numbers on the slide, is done 

 by maclunery. The names are printed upon the scale with 

 moveable steel types, and therefore advantage can be taken 

 of any improvements ; or any list of names can be printed, 

 to suit the particular wishes of chemists. 



We may remark farther, that Messrs. Hedge & Co. have 

 been engaired some time past in the manufacture of gun- 

 ter's scales and carpenter's rules, of every description. The 

 apparatus for effecting the graduations, is of a novel and 



