Holy sheep shit, ladies and gentlemen, I think I just figured out a way to deal with the copious amounts of HCN gas needed to make pure TlCN solution. TlCN can be precipitated from a solution of thallous nitrate by addition of aqueous potassium cyanide but the yield sucks. TlCN is NOT all that insoluble despite the way the literature reads. 100 grams of water dissolves 8.67 grams at 0°C, 15.17 grams at 14°C, and 29.57 grams at 31°C. The other way to make TlCN is to bubble HCN through a solution of TlOH. This reaction has to be done way back away from the house but up until now I've had serious concerns about going near it to adjust anything and especially breaking down the apparatus. HCN is lighter than air but not by a whole lot so I would imagine that it rises slowly. That gives me pause. But apparently this whole problem can be solved quite easily by simply breathing through a very long garden hose whose far end is way way away on the other side of the property. So long as I breathe in through my mouth and out through my nose I think it will work. I should stress this is only to buy me enough time to make whatever adjustment needs to be made or to open the apparatus to degas at the end. Sure in principle this should work perfectly. In practice having tried something similar already in the past I know its not quite that easy. But I think I can pull it off. Obviously don't try this at home kids.