252 Scientific Intelligence. 
to account for the formation of these curious compounds. This forma- 
tion can also be effected in a continuous manner since the reactions 
which produce it are incessantly renewed.”—Ann. Ch. Phys., December, 
866. 
10, Silvering upon glass—Having occasion recently to silver some 
To the second portion of the silver solution, caustic ammonia is added 
. 
film is protected by a layer of varnish. 
forms ver 
tube while vibrating, dropping down at the close of the motion, thus 
g 
: uty and distinctness appear, most readily in a closed, but also 
In an open, pipe. The whole pipe is divided into oval nodal spaces, dis- 
nt half a wave-length from one another, and between them we se@ 
fine, parallel and very distinct, nearly equidistant transverse ripplings, Te 
sulting from the transverse walls raised in the tube during the vibration. 
© experiment is so easily repeated (blowing by means of a bellows 
even the mouth) and the nodal figures so exceeding beautiful both dur- 
ing and after the intonation, and the same may so easily be P soaa 
thereafter, that every reader ought to repeat the experiment. ag 
the distance of any two nodal areas gives with great accuracy the b 
uccession—after 
wave-length of the tone; the same pipe may in quick s 
