Could we transmit smells electronically?
There are only three kinds of optical receptors in the eye, but more than 900 kinds of olfactory receptors. Thus you can encode pictures with the three primary colors, but there is no small set of primary scents. 

To transmit a smell via "primary scents", you'd have to create an artificial nose that monitors the response of each of the olfactory receptors, and then at the other end release a chemical mixture that has the exact same response pattern. (You won't find a one-to-one mapping of chemical compound to receptor.)