Virtual Museum > The early ones > slide rules
The JEFFERS CALCULATOR
This one is not exactly a calculator, in the sense that you will not be able to perform additions, or multiplications, however you will be able to calculate how much you need to feed your cattle !!
Yes, a cattle feed calculator. Let's have a look
This device was invented in 1907 by a gentleman named Henry JEFFER. The idea was to help farmers and calculate the daily rations for the cattle, based on the different type of food. A very mice idea, a very neat design and construction, but if you think of the mid-west in the early 1900, you don't think the farmers would be technology freeks !
Henry JEFFER has been working all his life in dairy farms, or other agricultural business. He invented a couple of devices, some very small, like the calculator above. But some others were much bigger, like the cow caroussel, where 50 cows were placed on a rotating tray , in order to minimize the movements of the milker.
Here is a picture of Mr JEFFER
The calculator was indeed well constructed, and here is a close-up of some details, showing the different sliders:
You can even see that the price, in 1907, was $5. You can wonder what was the cost of living in 1907, here are a few examples:
Yes, a cattle feed calculator. Let's have a look
This device was invented in 1907 by a gentleman named Henry JEFFER. The idea was to help farmers and calculate the daily rations for the cattle, based on the different type of food. A very mice idea, a very neat design and construction, but if you think of the mid-west in the early 1900, you don't think the farmers would be technology freeks !
Henry JEFFER has been working all his life in dairy farms, or other agricultural business. He invented a couple of devices, some very small, like the calculator above. But some others were much bigger, like the cow caroussel, where 50 cows were placed on a rotating tray , in order to minimize the movements of the milker.
Here is a picture of Mr JEFFER
The calculator was indeed well constructed, and here is a close-up of some details, showing the different sliders:
You can even see that the price, in 1907, was $5. You can wonder what was the cost of living in 1907, here are a few examples:
- The average wage in 1907 was 22 cents per hour.
- The average worker made between $200 and $400 per year.
- A competent accountant could expect to earn $2000 per year, A dentist $2,500 per year, a veterinarian between $1,500 and $4,000 per year, and a mechanical engineer about $5,000 per year.
Most of us are now thinking that we are born in the wrong time, if you are a mechanical engineer like me..
Well, to his credit, he proposed some smaller price for students. I wonder what is the relation between students and farmers.
Enjoy a small video showing this device below
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times since January 2017