Briggs.l 228 IMay. 



seventy-five dollars against two hundred and twenty-five, counting 

 the present cost of a bill of exchange. It is difficult to understand 

 how the Messrs. Becker can do justice to themselves, at such a price. 

 And not only was there a saving of money, but of time also. 



There is one other point worthy of a few words, — that we have here 

 a further development of the progress of delicate workmanship in our 

 own country. We proceed from clocks to watches, from reapers to 

 penknives. And in regard to philosophical apparatus, if we may 

 introduce names, it is well known that our Ritchie, at Boston, has 

 so improved upon RuhmkoriF, of Paris, in the powerful induction- 

 coil (the most splendid instrument of the day), as to entitle it to be 

 called by his own name, and to be counted American. 



It should be stated, that the balance will indicate the tenth of a 

 thousandth of the demi-gramme, which is our normal weight in the 

 gold assay; that is, it will turn with yg'oQth part of a grain. As 

 the beam and appendages are quite heavy, and capable of bearing 

 twenty times tbe largest weight ordinarily used, it might be made 

 much more sensitive by lightening the parts; but for woi'king pur- 

 poses, this is not desirable. Such a sensibility would serve to gratify 

 curiosity, or to make a boast of, but would not be in keeping with 

 the amount of deviation which is to be expected in other parts of the 

 assay — the cupellation and parting. It would be too much like the 

 exquisite refinement of some who report specific gravities : their 

 apparatus carries them safely to the second decimal, but their arith- 

 metic extends to the fourth or fifth. 



Dr. Wood made a verbal communication respecting Mr. 

 Harrison's steam boiler. 



Dr. Dawson's communication on the Coal of Nova Scotia 

 was read. 



Mr. Robert Briggs of Philadelphia, communicated through 

 the Secretary, extracts from a private professional statement 

 of his views of the true seat of reserved power in rolling-mill 

 machinery, and of the importance of using boilers of the 

 largest possible ivater capacity, for accumulating and storing 

 up the force to be expended, at intervals, with great rapidity, 

 in the passing of the iron through the rolls. 



Firstly. It is clear that in an extended mill, the waste heat of the 

 furnaces is far in excess of what is required to supply steam for 



