1815.] in the Physical Sciences. S\ 



TAcid 47-5 



Foliated oxalate of ammonia-) Ammonia 10*5 



and-copper y Peroxide of copper .... 25*0 



CWater 17O 



lOO'O 



TAcid 36-00 



Effloresced oxalate of ammo- j Ammonia 16*29 



nia-and-copper f Peroxide of copper . . . 39*00 



C Water 871 



100-00 



TAcid 43-00 



Pulverulent oxalate of ammo- J Ammonia 9-72 



nia-and-copper ^ Peroxide of copper . . . 45-58 



C Water 1-70 



100-00 



fAcid 72-15 ..'..36-075 



Sulphate of potash- ) Potash 42-85 21-425 



and-copper J Peroxide of copper ... 36-00 .... 18-000 



V Water 49-00 24-500 



200-00 100-000 



3. Chromates. — Dr. John has published a paper on the chro- 

 mates, in which he describes the properties of twelve chromates 

 hitherto unknown, or nearly so. As this paper is short, and cannot 

 well be abridged, I have inserted a translation of it in the last 

 number of the Annals of Philosophy^ to which I refer the reader. 



4. Sal-ammoniac. — Before concluding this department, I may 

 take the opportunity of mentioning that Mr. Trimmer informs me 

 that the sand employed for mixing with the clay by the London 

 brick-makers is brought from below Woolwich. It probably, there- 

 fore, contains some common salt, derived from the sea water with 

 which it Is washed. This may be the source of the muriatic acid 

 which goes to the formation of the sal-ammoniac that sublimes 

 during the burning of the bricks ; but if this be the case. Nature 

 employs during this process some method of decomposing common 

 salt at present unknown to manufacturers ; but which it might be 

 well worth their while to endeavour to trace expcrlincntally, unless 

 we suppose the whole acid to come from the muriate of magnesia. 



VIJI. Composition of Alcohol and Ether. 

 M. dc Saussure has given us a new, and seemingly very accurate, 



