78 ANNUAL OF SCIENTIFIC DISCOVERY. 



in which case a little water can be added. After they have been in the acid 

 about ten minutes, the ac^will be found to have penetrated to nearly the six- 

 teenth of an inch, according as the steel is good, bad, or indifferent. They 

 should be then taken out, and carefully immersed in water, to stop the action 

 of the acid, and then examined as to the quantity of carbon each contains, 

 which should be duly notified a sufficient quantity will be left on the etched 

 steel for this purpose the carbon undergoing no change from the action of 

 the acid. I would then rinse and dry them ; after this they can be safely 

 examined; the faults of each will be plainly palpable. The best will be 

 evenly etched, and dark in color, from the exposure of the carbon. The next 

 will be more uneven in surface, with more or less of carbon, according to its 

 manufacture. The next and worst will be rougher still, scabby, rough, or 

 rotten, as the case may be. If one should be found to be iron, it will be 

 deeper etched, whitish colored, and stringy in the grain. These are a few 

 of the distinguishing peculiarities which the acid brings to light. By this 

 process all the properties of steel or iron are exposed. If the steel be ' burn- 

 ed,' one or two minutes' immersion will be sufficient to detect it, its surface 

 will be etched in lines considerably apart, corresponding to the patched surface 

 which the steel exhibits previous to polishing." 



Purchasers of either iron or steel in large quantities should invariably use 

 it, as no imposition can be exercised without detection. Critical expedients 

 for detecting the qualities of metal are rather numerous as weight, for 

 instance. No two pieces of metal of exactly equal bulk, if of different quali- 

 ties, are of the same weight, &c. 



By the acid process, it will be seen that either natural or cemented steel 

 can be advantageously subjected to this test hi its manufacture. The process 

 of decarbonization hi the former, and of carbonization in the latter case, instead 

 of being left, as is now done, to the doubtful skill of the workman, can be 

 subjected to the unerring test of the acid. The manufacturer of steel might 

 get a scale of qualities which have been subjected to this test, marked Nos. 1, 

 2, &c., with such remarks to each piece as may be a guide to the workman 

 as to the time in its manufacture, the quantity of carbon found, and foreign 

 matter introduced, &c. Such remarks, with the decided peculiarities of each 

 quality of metal, will be a guide to any intelligent workman. 



WHAT IS THE ANNUAL WASTE OF IRON ON A FARM ? 



The London Mark Lane Express publishes the following communication 

 from an eminent English , ironmaster and agriculturist, in answer to the 

 question, " What is the annual waste of iron per acre in the cultivation of 

 land ?" the answer being based upon the careful examination of the accounts 

 of a farm in Bedfordshire, England. The farm consists of 330 acres of arable 

 land and 120 acres of meadow or permanent grass. The following is the list 

 of the implements employed upon it: 



6 Iron ploughs 1 Reaping machine 



2 Ridging do. 2 Horse hoes 



2 Double furrow do. 10 Carts 



1 Broad share do. 1 "Waggon and 1 van 



