Are methyl n-propyl ether and methyl iso-propyl ether metamers?

Are methyl n-propyl ether and methyl iso-propyl ether metamers?  

It says so [here](http://chem-guide.blogspot.in/2010/04/introduction-nomenclature.html). 


So the difference must be in number of carbon atoms or the distribution? 


Definition(<http://dictionary.reference.com/browse/metamerism>)




The term metamer is equivalent to isomer. Isomers differ in connectivites of atoms between molecules with the identical number and type of atoms.


Methyl *n*-propoyl Ether and methyl *iso*-propyl ether have the same numbers of carbon, oxygen and hydrogen atoms.


As an aside, I have never heard the term metamer before, I expect it is archaic.


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Compounds having the same molecular formula but different number of carbon atoms ( alkyl groups) on either side of functional group ( i.e., $\ce{-O-,-S-, -NH-, -C(=O)-}$) are called metamers and the phenomenon is called metamerism. metamerism occurs amongst the members of the same homologus family.


For example:


* $\ce{CH3CH2-O-CH2CH3}$ is a metamer of $\ce{CH3-O-CH2CH2CH3}$ OR $\ce{CH3-O-CH(CH3)2}$
* $\ce{CH3CH2COCH2CH3}$ is a metamer of $\ce{CH3COCH2CH2CH3}$ OR $\ce{CH3COCH(CH3)2}$


It may be noted that metamers may also be position isomers, e.g., pentan-2-one and pentan-3-one may be regarded as position isomers as well as metamers.


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It is a type of positional isomerism in which functional group changes its position in the backbone of parent chain,methyl propyl ether and methylisoptopyl ether are metamers from Above def. 


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