144 WE FARM FOR A HOBBY 



tin cans (it is perfectly feasible to can in tin at 

 home: vide the mail-order catalogs). A quarter of 

 an inch of water is put in the bottom of the kettle 

 which is then loaded with jars. A heavy aluminum 

 lid is bolted on securely with a strong collar. A 

 petcock in the lid is turned wide open, the heat 

 under the kettle set full blast. When all the air 

 has been driven out and only steam remains in the 

 kettle the petcock is closed. The rise of tempera- 

 ture within the kettle is thereafter indicated to the 

 uninitiate by a thermometer, to those of us who 

 belong to a vanishing civilization by a "pressure 

 gauge." Once the cook anywhere but on a farm 

 it would have to be a licensed engineer has 

 brought the pressure inside the machine to the de- 

 sired stress it must be kept there for varying 

 lengths of time, according to what is being canned. 

 When the cooking i.e., sterilizing is done the 

 machine is allowed to cool down until it can be 

 opened without scalding the operator; it is then 

 opened and the jars are removed and sealed tight. 

 There are two other advantages in pressure- 

 cooking beside that it makes for better preserva- 

 tion. One is that with certain vegetables the total 

 time for preparation and canning can be cut con- 

 siderably below open-kettle canning. This applies 

 especially to such things as corn that take hours 

 of boiling by open-kettle, and then probably will 

 not keep; it is not true of tomatoes, or fruits that 



