With his first find, Marshall hurried off to Sutter, at the ranch. Together they tested the flakes in the apothecary's shop, proving the reality of the discovery before returning to the mill to prospect more fully.
For Sutter the discovery was a calamity. None could tell how large the field might be, but he saw clearly that once the news of the find got abroad, the whole population would rush madly to the diggings. His ranch, the mill, and a new mill which was under way, all needed labor. But none would work for hire with free gold to be had for the taking. The discoverers agreed to keep their secret for six weeks, but the news leaked out, carried off all Sutter's hands in a few days, and reached even to San Francisco in the form of rumor before February was over. A new force had appeared to change the balance of the West and to excite the whole United States.
The rush to the gold fields falls naturally into two parts: the earlier including the population of California, near enough to hear of the find and get to the diggings in 1848. The later came from all the world, but could not start until the news had percolated by devious and tedious courses to centres of population thousands of miles away. The movement within California started in March and April.
Further prospecting showed that over large areas around the American and Sacramento rivers free gold could be obtained by the simple processes of placer mining. A wooden cradle operated by six or eight men was the most profitable tool, but a tin dishpan would do in an emergency. San Francisco was sceptical when the rumor reached it, and was not excited even by the first of April, but as nuggets and bags of dust appeared in quantity, the doubters turned to enthusiasts. Farms were abandoned, town houses were deserted, stores were closed, while every able-bodied man tramped off to the north to try his luck. The city which had flourished and expanded since the beginning of 1847 became an empty shell before May was over. Its newspaper is mute witness of the desertion, lapsing into silence for a month after May 29th because its hands had disappeared. Farther south in California the news spread as spring advanced, turning by June nearly every face toward Sacramento.