92 DIVERS AND HAÖA. 



H. /SOsAm), 

 may lie formulated as J ; /^\ , aiid fhe similar compound 



■(NO3K ^Na 

 of dipotassium imidosulphonate. Lastly, there is the moi-e-basic lead 



salt described in the Inst part of the pi'evious section of this paper. 



Tills may be written | )^^ or (H())N^ .if we, 



(V \PbOH ^(PbOH)2 



allowably by the an:dysis, reject or admit tlie presence of one molecule 

 of water. 



Silver imidosid'plionates^ singk and double. 



Silver nitrate and tri sodium imidosulphonate will yield three 

 different compounds, in which one. two, and three atoms of sodium 

 are replaced by silver. Such an nnnsna.l behaviour in the salt of a 

 polvbasic acid gives to imidosulphonic acid a special interest. 



• The addition of siher nitrate in limited quantity onuses a white 

 precij)itate which redissolves to be ra])idly followed, unless the 

 solutions are very dilute, by the separation of another comp(3und. 

 This consists of interlacing fibrous crystals filling the liquid as a 

 felted mass, even when pi-esent in only small quantity. Tluis, the 

 wliole m:iv be well stirred and yet afterwaixls j^rove a])le to support 

 the stirrei" awuv from the sides of the Ijeaker, th(jugh the actual volume 

 of the salt, separated frojn its liquor and pressed, may be a small 

 fraction of the wlxjle. 



Further additions of silver nitrate to the liquor and crystals 

 cause geuerally more of -the first white precipitate, and after that, 

 when in sufiicient quantity, the disap[)e;jrance of both the preci])itates 

 together. The new solution becomes almost immediately full of n 

 third precipitate, this time of very dense, h-u'd, minute, separate 

 crystals, which rapidly subside into a deposit that in appearanci^, in 

 grating under the stirrer, and in movement when disturbed, most 



