238 Intelligence and Miscellaneous Articles. 
trically and magnetically insulated from each other: so much for the 
second point of dissimilarity, or rather identity. 
The interruption of contact in Mr. Bentley’s machine, which he 
says I noticed as peculiar, did not proceed, as he states, from any 
modification of the wire, but from his having adopted my stiff spring, 
which is one of the distinctive characteristics of my machine, and a 
point of identity which Mr. Bentley does not find it convenient to 
allude to. 
The rapid vibrations and modified appearances of the sparks are 
as peculiar to my machine as to his, and I have also the power of 
varying them at pleasure. I confess that I should like to know by 
what means Mr. Bentley has arrived at the conclusion, that his 
spring has ever vibrated 2000 times per second; I think he must 
have inadvertently inserted one cipher too many, or made an erro- 
neous guess. 
Again, Mr. Bentley states that another feature of dissimilarity is, 
that he uses a number of coatings of thin gutta-percha in preference 
to fewer layers of thick tissue, &c. If Mr. Bentley will refer to 
the Philosophical Magazine for December 1856, he will find that I 
use a stratum of oiled silk or sheet gutta-percha between the layers. 
I have also used thin vulcanized india-rubber tissue, and I use the 
thinnest material I can get, in a number of layers precisely as he 
describes. Thusit appears that Mr. Bentley’s falsely assumed points 
of difference are really all points of the most perfect similarity, and 
that to identify his name with his coil is a complete piece of pla- 
giarism. I will now take the liberty of pointing out the peculiarly 
distinctive features of my coil as compared with that of M. Ruhm- 
korff, and show how these distinctive peculiarities have all so 
strangely appeared in Mr. Bentley’s machine. 
lst, then, Ruhmkorff’s secondary wire is covered with cotton; 
mine is covered with silk, and so is Mr. Bentley’s. 
2nd. Ruhmkorff insulates the layers of his secondary wire with 
paper; I use gutta-percha, and so does Mr. Bentley. 
3rd. Ruhmkorff uses a hammer at the end of a lever, resting by 
its own gravity upon an anvil, to break contact; but I use a very 
stiff spring for the purpose, the vibrations of which I can modify at 
pleasure, and so does Mr. Bentley. 
4th. Ruhmkorff uses iron rods about a quarter of an inch thick for 
the core of his machine; I use thin wires electrically and magneti- 
cally insulated from each other, and so does Mr. Bentley. 
5th. Ruhmkorff for his condenser uses about twelve or fourteen 
feet of tinfoil folded between sheets of oiled silk. I have used oiled 
silk, vulcanized india-rubber, gutta-percha, cartridge-paper, and var- 
nished paper, and I make my condenser of very large dimensions, 
Mr. Bentley uses varnished paper and does the same. 
These peculiarities of my machine were all thoroughly known to 
Dr. Noad more than six months before he and Mr. Bentley brought 
out the machine in question; and I may be pardoned for reassert- 
ing, though it should be for the fifth time, my claim to be con- 
sidered as the originator of this new form of induction coil in 
