Sparkles

I have done several searches in library databases, police precincts, and city hall to discover all that I could about this building that my current tour group wants to see. I needed to discover as many facts (and rumors) before I brought them so I could answer their questions and they do have a lot of questions. I have done multiple searches trying to find buildings that meet their very specific criteria:
 

physical structures in the greater Hudson Bay area --

that predate Joseph von Fraunhofer's 1814 invention of the spectroscope --

which continue to stand in their original site --

and consist mostly or completely of the original materials.

Then they add an address in the 130 block of Degraw street in Brooklyn of all places. This building is maybe 1820's or 1830's which is later than their requirements. I decide that I need to actually look at this building. I arrive and scan it from the street. I see nothing special - except the For Sale sign. However, with a lawsuit in progress that was an expected aberration. I walk up to the front door and knock, but there is no answer and neither the front door, nor the side windows offer the ability to look inside.
 
I decide that I really need to see inside so I climb on top of the railing, brace myself, and get to the top of the porch roof. I peer into the 2nd story window and, while there are window blinds, there is a gap and I can see into the room. It is dim, but it looks like there are construction tools and a too tired to recycle recliner. I can see a glimpse of sunlight in the hallway, but no people. I start looking for a way to get over to another window. I see that at the other end of the porch is a window that has some anti-theft or maybe window guards to keep anyone from accidentally falling out. But that guarding is only on the bottom of the window and there is a lovely gap where a talented (and amateur!!) thief could jimmy open the lock, lower the top half of the window and enter the premises. I do so and then carefully close the window to minimize the chance of anyone noticing a change in the street view.
 
I take a moment to sense the environment. Ambient noises and the sounds of a foreign language I have heard in the past, but not often or recently. Cool inside and the light is bluish which makes it look like the windows might have some kind of treatment. There also seems to be what was a floating floor, but it has degraded since installation in the 90's. There is also a lot of evidence of multiple attempts at interior design, but nothing that was a good idea. I walk over to the hallway and I see another larger, longer stream of a cubic sparkle that seems to be going downward in a northly direction and once it leaves the building - the language abruptly stops!
 
I start following the sparkles