waste that accumulate each year in germany a mineralogist that they're falling off the institute for building physics has come up with an unusual answer. we want to decompose this used concrete into its components by shooting ultra short lightning polson started going to force a lightning into the concrete we put it under water otherwise the post would dissipate in the air and nothing would happen. the idea was originally developed by soviet scientists back in the 1940 s. . adapted the method in order to break down waste concrete into its individual components in his lab the. the decisive factor is the ultra short electrical poles he generates. and i've got a picture of it here 1st we get many many flashes of lightning that wander along the surface and cause extreme mechanical weakening of the material. channel forms in the material and grows rapidly producing a pressure wave that says powerful as a t.n.t. explosion. did it. and the result at 1st it's a murky sludge but soon course particles grow visible. the gravel has been cleanly separated it could be used as a building material straight away. wha

building up for decades, and part of what was going on in congress is that southern slaveholders were protecting that institution by threatening and intimidating and occasionally really being physically violent towards anyone who opposed them. >> the title "there will be blood" comes to mind. when was there blood? >> well, in one case, one congressman actually killed another congressman in a duel in 1838. but for the most part, what you see a lot in congress -- i mean in a sense, it's not unlike some of what we're seeing today. the point of it wasn't necessarily to shed blood. it was to score points. it was to make a point. it was to silence people through intimidation. so it wasn't necessarily about bloodshed. it was about bullying more than anything else. >> talk about how firearms were viewed, were carried. were they on a per capita, prorated basis for pervasive and likely to be used than today? >> well, for sure there was a lot of firearms in this period around. but if we're talking specifically about congress, there were a good number of congressmen who were armed. southerners were more likely to be armed for a time than northerners, sometimes with pistols, sometimes with bouie