All genuine walking liberty half dollars are 90% silver for all years. Unless there is an obvious reason why it wouldn't be silver (wrong year, wrong design, plating flaking off, etc.) it is safe to assume it is silver. There are a few contemporary and modern counterfeits of Walking Liberty dollars but they are easily spotted.
Check that coin again, because what you're describing doesn't actually exist. There were no silver dollars minted that year, and the Walking Liberty design (on the half dollar) wasn't introduced for another decade.
Please turn the coin over and check the denomination on the back. You'll find it's a HALF dollar.
Please check your coin again. The Walking Liberty design was used on HALF dollars during the 1930s, but there were no half dollars or silver dollars minted in 1930 due to the Great Depression.
Please check the coin again and post new question, the Walking liberty design was first used on half dollars in 1916 not dollars in 1878.
Please check your coin again and post a new question. The Walking Liberty design was used on HALF dollars 1916-1947 but no halves were minted in 1926. Silver dollars carried the Peace design.
Please check the back of the coin. You'll find that it's a HALF dollar. See the Related Question for more information.
The last US silver dollars were minted in 1935. Please turn your coin over and check the denomination on the back. If it has a Walking Liberty design on the front, you'll find that it's a HALF dollar.
To a collector, whatever he's willing to pay. To a coinshop, its weight in scrap silver only. Check silver prices.
Please look at the coin again. The only U.S. DOLLAR coin dated 1978 is an Eisenhower Dollar. The Walking Liberty design for the American Silver Eagle dollar coins was first issued in 1986. Please post new question with more information.
Please turn the coin over and check the denomination on the back. It's a half dollar, not a dollar. There's more information at the question "What is the value of a 1946 US half dollar?"
Please check again and post a new question. The U.S. didn't mint any silver dollars after 1935. If your coin has the famous walking Liberty design on the front it's a HALF dollar.
Please check the coin again and post new question. The Walking liberty design was first used on half dollars in 1916.A genuine 1836 US silver dollar would have a picture of a seated Miss Liberty on the front and a flying eagle on the back. 1836 is a fairly rare date for Seated Liberty dollars so any such coin should be authenticated by an expert.If your coin really has an 1836 date and a Walking Liberty design it's a badly-made counterfeit.