As I wrote last month, the early California gold miners began with placer mining, simply picking the nuggets off the ground or from streams, with hands and pans and knives. Soon, however, they wanted to sift through more dirt faster to increase the profitability of their prospecting.
One of the earliest tools they employed to speed their collection of gold flakes and nuggets was the rocker—also called a cradle because it resembled a child’s cradle. The rocker was merely a way to pan for gold more quickly. The rocker moved more water and rock than the miners could by hand.
In essence, the rocker was a box into which the prospectors shoveled both dirt and water. The box had a handle that they pushed back and forth. Like the swishing motion of panning, this rocking caused heavier material to sink to the bottom of the device. The miner then panned the leftover sediment to find gold.
Colonel Richard Mason gave an excellent description of how a rocker worked in his July 1848 report, in which he wrote that most miners were employing “a rude machine known as the cradle.” Here is his description:
This [the cradle] is on rockers, six or eight feet long, open at the foot, and its head had a coarse grate, or sieve; the bottom is rounded, with small cleets nailed across. Four men are required to work this machine; one digs the ground in the bank close by the stream; another carries it to the cradle, and empties it on the grate; a third gives a violent rocking motion to the machine, whilst a fourth dashes on water from the stream itself. The sieve keeps the coarse stones from entering the cradle, the current of water washes off the earthy matter, and the gravel is gradually carried out at the foot of the machine, leaving the gold mixed with a heavy fine black sand above the first cleets. The sand and gold mixed together are then drawn off through auger holes into a pan below, are dried in the sun, and afterwards separated by blowing off the sand. A party of four men, thus employed at the Lower Mines, average 100 dollars a-day. The Indians, and those who have nothing but pans or willow baskets, gradually wash out the earth, and separate the gravel by hand, leaving nothing but the gold mixed with sand, which is separated in the manner before described.
As a later commentary said in describing the work required to operate a rocker,
The man who rocks a cradle learns to appreciate the fact, that the “golden sands” of California are not pure sand, but are often extremely tough clay, a hopperful of which must be shaken about for ten minutes before it will dissolve under a constant pouring of water. Many large stones are found in the pay-dirt. Such as give an unpleasant shock to the cradle, as they roll from side to side of the riddle-box, are pitched out by hand, and after a glance to see that no gold sticks to their sides, are thrown away; but the smaller ones are left until the hopperful has been washed, so that nothing but clean stones remain in the riddle, and then the cradler rises from his seat, lifts up his hopper, and with a jerk throws all the stones out.
The next development in the California gold fields was the use of the Long Tom, which looked like a long trough. These devices were used extensively by 1851. The box of a Long Tom was typically eight to twenty feet long, and it had riffles to catch the gold and heavier debris. A constant flow of water was needed to force the gravel along the trough. Miners shoveled gravel into the upstream end of the box. As with the rocker, the heavier gold sank to the bottom of the gravel, and could be panned from the gravel.
To get the necessary water, the prospectors either placed their Long Toms in streams or they diverted water through Long Toms near the water. Sometimes, the tom was connected to a paddlewheel that moved the water through the device.
The Long Toms had more capacity than rockers and didn’t require the work to rock the machine. Still, two or more men were required to work the device. If there were only two men available—one shoveling gravel into the tom, and the other keeping it clear of rock, they could wash about 6 cubic yards of loose gravel, or 3 to 4 cubic yards of cemented gravel, in a ten-hour day.
Usually, four men operated the Long Tom—two shoveling gravel into the top end of the device, and another to clear out larger rocks along the trough. A fourth man worked the lower end to get rid of smaller rocks (the tailings). More men made the job more efficient, so more gravel could be processed.
Even without the rocking action, manning a Long Tom was hard work. As Johnson wrote,
The dirt is thrown in at the head of the tom, and a man is constantly employed in moving the dirt with a shovel, throwing back such pieces of clay as are not dissolved, to the head of the tom, and throwing out stones. From two to four men can work with a tom; but the amount of dirt that can be washed is not half that of a sluice. The tom may be used to advantage in diggings where the amount of pay-dirt is small and the gold coarse.
No wonder sluices soon became popular in the California gold mines.
What labor-saving devices have you seen develop in your lifetime? What do you think the next technical innovations will be?