Price of gold in 1900 was fixed by the government (dollar to gold value was set by them- not a free market). But let's look at the numbers anyways. In 1900, an ounce of gold was $20.67.
http://onlygold.com/TutorialPages/Prices200Yrsfs.asp Average annual income was about $450
http://articles.chicagotribune.com/...homes-two-or-three-bedrooms-new-housing-units or 21.8 ounces of gold.
In June, 2013, US median income was $52,100
http://www.nytimes.com/2013/08/22/u...-but-is-still-6-below-its-2007-peak.html?_r=0 and with gold about $1300 an ounce, that comes to "earning" 40 ounces a year or nearly twice as much gold per hour as 1900 or in other words, you need to work half as long to aquire the same amount of gold.
Or- in terms of incomes, gold has lost half its value since 1900.