JEFFER calculator - Francis WEB

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:

• 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