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A few years ago, we left our home in sunny Florida and traveled out west. One of the places we visited was the gold country near Sacramento at Coloma, California. This is the famous location of Sutter's Mill where James W Marshall discovered gold on 24 Jan 1848. John Sutter and James Marshall tried to keep the discovery quiet initially – and it worked for a while. However, teamsters delivering supplies to the sawmill were paid in gold dust and soon the word began to spread. The informational dam burst on 14 May 1848 when Sam Brennan published an article in his San Francisco newspaper about the gold strike. His newspaper was shut down shortly after that because even his own employees had caught the fever and headed for the hills. Then in December, President Polk mentioned the gold discovery in an address to congress. This validated the rumors and helped trigger a world-wide gold rush to California.

At Coloma, there are several exhibits that commemorate these events and the hardy souls that came to the area to strike it rich. Few did. Even James Marshall died a pauper. However, the fervor that was generated helped open up the West and added to the colorful history of the United States. The exhibits at Coloma are also a tribute to man's ingenuity (however misguided) as more and more efficient methods were found to coax the earth to relinquish its precious metal.

Sutter's Mill

Sutter's Mill – This is a replica of the mill where James Marshall found gold in 1848. It has the accompanying plaque:

Mining techniques changed over the years. Panning led to sluices with shakers, hydraulic mining with monitors, and finally to dredges with huge buckets. Along the way, more efficient ways were found to crush the rock. The pictures below depict some of this technology.

Hydraulicking also swept large amounts of silt and gravel into the Sacramento and San Jaoquin rivers, causing frequent flooding. Valley farmers organized and an 1884 court decision made hydraulic mining operators liable for downstream damage. As a result, most companies found further hydraulicking unprofitable and the industry came to an end.

I hope you enjoyed this brief tour through the birthplace of the California Gold Rush. If you get to northern California someday, visit the Marshall Gold Discovery Historic State Park at Coloma and see the rest of the exhibits.

SUDOKU Puzzle Solver

Our local newpaper started carrying SUDOKU puzzles recently. They are simple math puzzles where a 9 by 9 matrix is filled with nine 3 by 3 submatrices. When the puzzle is solved, the rows and columns of the 9 by 9 matirix and each of the submatrices all contain the digits 1 through 9 and, of course, add up to 45. Initially, the matrices are partially filled in and the task is to fill in the empty spaces. The solutions for the puzzles are easy but sometimes tedious. I figured that the real challenge was to create a program that would solve the puzzles for me. Being an "old school" programmer (I'm 61), I used my favorite language to write the program, FORTRAN. Because I'm lazy and didn't want to have to type in all the seed numbers in the matrices, I built a graphical interface to the puzzle solver. The program is started by running the GSU.EXE file, maximizing the windows and bringing the slider bar on the right all the way to the bottom. You should then see the 9 by 9 matrix and submatrices. The value zero is initially assigned to all the cells in the matrices. This corresponds to blank cells in the puzzles. Each cell also contans two rows of digits, 0 through 4 in the first row and 5 through 9 in the second, You simply click on the appropriate number (1 through 9) in each cell to assign that number to the cell. If you make a mistake, you can click on zero (0) to return that cell to the "blank" state or click on another number to change the cell to that value. When you are finished filling in the numbers provided in the puzzle, you click on "DONE".

If the puzzle solver fills in all the numbers in the matrices, the puzzle is solved. Click on "DONE" again to get confirmation of the solution. If the puzzle solver cannot figure out the whole puzzle, the possible values for all the cells that still have zeros will be highlighted. At this point you can choose a highlighted value and click "DONE" once again or click checkpoint "CKPT" to save the values that have been figured out so far. If you choose a value that results in an impossible solution, the puzzle will revert back to either the original entries or the values that you have checkpointed, and you can try again. I have seen the solver fail to get the correct solution on the first try once (so far). In that case, I guessed at an answer from one of the highlighted choices and after a few tries, the puzzle was solved. (I'm still trying to figure out how to avoid guessing on that puzzle.)

I know that lots of folks don't like to run .exe files (I'm one of them). However, I can assure you that there are no viruses contained in this program and it is perfectly safe to run. If you cannot support the graphics or don't have enough memory, it may not run, but it will not do any damage to your system. I'm posting the program because it was fun to write and I would like to find out if it works on other windows based systems. I've only tested the program on my home computer and laptop (both running Windows XP). If the program does or doesn't work on your configuration, I'd like to know. You can contact me using the e-mail link below. If you're interested in the code, I can be persuaded to share it (you will need an HP FORTRAN complier to use the graphics calls).

To download the puzzle solver, click here (344 kilobytes)

Here's a sample puzzle:

Here's the puzzle that I didn't solve automatically:

Here's that puzzle solved - It would have solved automatically if any one of the cells in red had been part of the original puzzle:

By the way, the puzzle solver can also be used to make your own puzzles by filling in partial matrices and seeing what happens.