ENGINEERING AND ARCHITECTURE. 395 



From the3e it appears, that ia moderately dilute solutions the whole of the sul- 

 phuric acid is precipitated by the addition of very little more of the barium salt 

 than is theoretically required, but if the dilution be very great then a loss oc- 

 curs, which, however, is not found if any excess of the precipitant be employed. 

 As we do not generally precipitate from very dilute solutions, and always employ 

 an excess of the precipitant, no danger need be apprehended from the presence 

 of free hydrochloric acid. Mr. Noad points out, however, that fuming nitric 

 acid often contains sulphuric acid, although it does not give any precipitate with a 

 salt of barium when diluted. By driving off the greater part of the acid, and then 

 diluting, the presence of sulphuric acid may be detected. — Quar. Jour, of Chem. 

 Soc. No. 33. 



Affinity. — Dr. Gladstone has published a lengthy investigation into the "Cir- 

 cumstances modifying the action of chemical affinity," which does not admit of an 

 abstract. — Phil. Trans. 1855, p. 179. Quar. Jour, of Chem. Soc. No. 33. 



Ammoniums. — T. Weltzien has published a very interesting paper on the " Am- 

 monium Molecules of the Metals," and proposes an ingenious theory by which the 

 formula? of the anomalous compounds of ammonia with the haloid and oxy-salts, 

 the ammonia-cobalt salts of Fremy, and the platinum, palladium and iridium com- 

 binations, are reduced to very simple and rational expressions. The paper can 

 scarcelv be abstracted without occupying more space in the Journal than the che- 

 mical department may justly claim. — Ann. der Ch. iu Pharm. 97, 19. H. C. 



ENGINEERING AND ARCHITECTURE. 



A NEW STEAM HAMMER. 



Mr. Naylor, the Norwich superintendent of the locomotive department of the 

 Eastern Counties Railway, has just succeeded in completing an important invention 

 in the form of a steam hammer, which he believes to be, in many respects, superior 

 to any other that has yet been constructed. Its peculiar qualities consist in its adap. 

 tation to all descriptions of work brought under it. It can deal with a small piece 

 of iron with the greatest precision, be it ever so small, or it can efficiently operate 

 upon a piece of iron six or seven inches thick. Such is the command over it 

 that it can be made to strike a light or heavy blow at will, and, if necessary, the 

 'ight and heavy blows can be given alternately, while it is dealing 200 blows a 

 minute. The rate of working may, moreover, if desired, be reduced to less than 

 100 blows per minute. Most power hammers obtain their force by their accelerated 

 velocity in their fall. Consequently when working upon a large piece of iron, the 

 greatest force is necessary; but, as the distance of the fall of the harnmeris reduced 

 by the thickness of the iron it is operating upon, the full power of the hammer 

 cannot be exercised. Mr. Naylor has, however, a provision for this difficulty, for, 

 by hi-! peculiar and patented arrangements, he can put any amount of steam power 

 upon the hammer iu addition to its own gravity, and it matters not, therefore 

 whether the hammer falls through a space of six inches or six feet, so long as its 

 velocity is the same at the instant of its contact with the iron on the anvil. The 

 steam can be applied above as svell as under the piston of the hammer, or, by merely 

 turning a small handle, the fteani is prevented entering into the top of the cylinder, 



