Alter is credited with having invented:
*1836 - the electric telegraph, predating the Morse telegraph in 1837. 
*1840 - his electric buggy - the forerunner of the automobile.
*1845 - a patented method to manufacture and purify bromine from salt wells, highly useful in the iron industry and displayed in the World's Fair of 1853 (see: Exhibition of the Industry of All Nations in New York City). 
*1854  - spectrum analysis, the idea that every element has its own emission spectrum: a breakthrough development in spectroscopy. The published article was: On Certain Physical Properties of Light Produced by the Combustion of Different Metals in an Electric Spark Refracted by a Prism. He included a chart of the colored lines or bands of twelve metals and paved the way by showing the spectral lines of brass corresponded to copper and zinc. 
*1855 - an expansion of spectrum analysis to include the optical properties of gas. These discoveries were later implemented and included by Gustav Kirchhoff and Robert Bunsen in the Three Laws of Spectroscopy.
*1858 - a patented method to extract oil from coal and shale, along with a partner Samuel Hill. Their invention sped manufacturing, but was replaced by technology in a few years.
*An electric clock.
*A short range type of telephone - forerunner of the Graham Bell telephone.