102 Correspondence of J. NickUs. 



Chinese paste, like the European, is composed of a variable mixture of 

 kaolin, that is of a material infusible in the heat of the porcelain furnace, 

 and of material which is fusible ; the glazing is of fusible material. This 

 is the analogy. The difference is that the fusible material mixed with 

 the composition in China is flint, but at Sevres it is composed of sandy 

 matter' coming from the washing of kaolin and chalk. The glazing of 

 Chinese porcelain is flint mixed with lime and frequently with frit. The 

 glazing at Sevres is of pure flint. The porcelain of China is less resist- 

 ant to fire than that of Sevres. The Chinese do not, like the Japanese 

 and Europeans, apply the glazing to the biscuit. There are other differ- 

 ences in the application of the coloring matters and in the composition of 

 some of the varieties. The typography of this work does honor in every 

 respect to M. Mallet-Bachelier. 



Peculiar arrangement of a Voltaic Battery. — This battery is designed 

 for medicinal uses. It has been contrived by a constructor at Paris, M. 

 Breton, and is maintained in a state of constant moisture with chlorid of 

 calcium. For one of the poles there is a mixture of copper filings with 

 saw-dust, the latter designed to separate the metallic particles, — the 

 filings are mixed with a solution of chlorid of calcium. The other pole is 

 a similar mixture in which the copper is replaced by zinc filings. These 

 two preparations placed in a vase and separated by a porous cell, make a 

 battery which has always the same intensity of action on account of its 

 constant humidity and the indefinite number of its elements. 



The natural state of Hippuric Acid. — So great differences exist in re- 

 gard to the proportions of hippuric acid contained in the normal state in 

 the urine of the horse, that a chemist, M. Roussin, has undertaken to find 

 out whether these differences are those of calculation or are really well 

 founded. After numerous determinations, he has recognized the fact that 

 the proportions of hippuric acid vary like the urea according as the horse 

 is at work or rest. The following table contains the results of the trials. 

 The urea has been determined in the condition of dry nitrate. 



Hippuric acid Nitrate of urea 

 in 1 litre. in 1 litre. 



1. Omnibus horses, 7*8 grammes 



2. " " at work, 10-0 " 18 grammes 



3. Arabian stallions, completely quiet, . . 0-0 " 32 " 



4. " " " " 0*0 " 35 " 



5. " " " " 0-0 " 33 " 



6. " " " " .. 0-0 " 34 « 

 1. " horses at work, 5'0 " 21 " 



8. " horse fatigued by a long course, 13*0 " 12 " 



9. " horse after a very long course, 14*0 " 15 



Hence it is clear that horses fatigued produce much hippuric acid and 

 comparatively little urea. Horses well fed and quiet produce little or no 

 hippuric acid. Urea on the contrary is found in their urine in very large 

 proportions. Its limpidity may be the index. If the liquid is clear and 

 deposits little carbonate of lime it has much urea and little hippuric acid ; 

 if it is muddy, it is certain that there is much hippuric acid. Respiratory 

 activity and the employment of muscular force accordingly seem to trans- 

 form urea into hippuric acid. Rest, on the contrary, leaves the urea in- 

 tact, and does not appear to favor its transformation into hippuric acid. 



