In my house is a fire extinguisher which boasts of sodium bicarbonate as a medium for extinguishing fires. It is powder under pressure. My High school experience tells me that gases are also compressible. Therefore, the fire extinguisher could have been filled with a gas suitable for dealing with fires. I have observed that there is a great variety of bottles and small and large containers already in use for carrying compressed gas. Here is where my school experience leaves me uncertain. I would appreciate it if someone could advise me whether carbon dioxide is readily compressible. If it is, then we all know where there is an enormous amount of carbon dioxide going to waste from huge chimneys all over the world ! Could that be compressed ? One wonders if compressed carbon dioxide could be used for fighting fires. Here again, I call for help. Perhaps a chemist or an engineer would be able to look at the proposition because I don’t know whether the gas is easy to work with. and I am not sure of the quantities available. I don’t think the quality is of any consequence, and scientists such as David Suzuki tell us that the CO2 produced from coal burning is contributing enormously to global warming, and that the amount pumped into the atmosphere runs into millions of tonnes. Right now I am in Yarrawonga where the smoke from dozens of fires is masking the sun. I can smell smoke which presumably contains CO2. Therefore those fires are creating CO2. The CO2 coming from coal burning is right now entering the atmosphere. If enough of it could be compressed, then used to fight fires as it enters the atmosphere, it would at least be of that much use. A tanker load of gas ( in this case CO2) , decompressed as it is used to fight a fire should produce many, many times the volume from a similar tanker of water. It may be that a knapsack containing CO2 would prove a useful tool. It also occurs to me that the compressed CO2 used occasionally in a liquid form might be suitable for extinguishing fires more rapidly. Please don’t see this as a crank letter. At least give it some thought. You may be able to pass the idea on to an authority. Ron Neilsen, Box 206, Yarrawonga, 3730.