Michael Collins

Brand builder. Former photographer.

[Michael Collins @collinscentral]

@jnack Oh man, that’s tough. Prepping myself for this in a few years. 🥺

[Michael Collins @collinscentral]

@TPCarney Fun read.

Does the kudzu cross the property line? It seems like you will need the participation of your neighbors to really keep the kudzu at bay. That's certainly been my experience with managing weeds in the lawn.

[Michael Collins @collinscentral]

@leylaaa31 4th of July on the Mall

[Aakash Gupta @aakashgupta]

That water clarity is an engineering decision, and the math behind it is wilder than the video.

Roman aqueducts ran on gravity alone. No pumps, no pressure systems. Engineers carved channels with a gradient so shallow it borders on absurd. The Pont du Gard in southern France drops 2.5 centimeters over 275 meters. That's roughly the thickness of a coin over the length of three football fields. They surveyed that accuracy with plumb lines and wooden leveling instruments.

The clarity you're seeing is a direct product of flow velocity. Too steep and the water erodes the channel walls, picks up sediment, turns brown. Too flat and it stagnates. Roman engineers targeted a slope of about 20 centimeters per kilometer, which kept the water moving fast enough to stay fresh but slow enough to stay clear. Before the water reached the city, it passed through multi-chamber settling tanks where velocity dropped near zero. Suspended particles sank. Clean water flowed out the top into the next chamber. Repeat three or four times.

Pliny specified the minimum slope in writing. Vitruvius published the exact mortar ratio for hydraulic cement: one part lime to two parts volcanic ash for underwater work. The pozzolana from Pozzuoli reacted with water to form a calcium-aluminum-silicate compound that actually gets stronger the longer it sits submerged. Modern concrete degrades in water. Roman concrete bonds with it.

Scale the whole system and it gets harder to process. Eleven aqueducts fed Rome at its peak. Combined output: roughly 1 million cubic meters of water per day. That works out to about 250 gallons per person for a city of one million. Modern New York delivers about 125 gallons per person per day. Ancient Rome had access to double the per capita water supply of the largest city in the United States, running entirely on slope and stone.

The Trevi Fountain in Rome is still fed by one of them. Two thousand years, same source, same gravity, same water.

[Jarrett Walker @humantransit]

Automated (driverless) operation of rapid transit is routine in many countries but no existing US rapid transit line has been converted to driverless. It could unlock a lot of frequency! Looks like @wmata in Washington DC will be the first.

[Michael Collins @collinscentral]

@ebloch @scottlincicome @LynAldenContact She was his wife for 59 years; that’s not her age.

[Michael Collins @collinscentral]

@mkobach I’ve watched another version of this video on instagram multiple times and it gets me every time. I’ll miss these years when they are gone.

[Michael Collins @collinscentral]

@Scholars_Stage It's funny to me how disdainful other economists are of Cowen (and others at GMU). They think he is wasting his time popularizing economic ideas and that peer-reviewed publications are the only real game. I'm a big fan of his multi-front intellectual blitzkrieg approach.

[Will Manidis @WillManidis]

typos are increasingly proof of work for humanity

[Michael Collins @collinscentral]

@Nicolascole77 Books

[Michael Collins @collinscentral]

@craftian_keskin Was this made with Midjourney? Or something else?

[Michael Collins @collinscentral]

@barrysvrluga @PostSports If anyone was being retained as a cultural sports columnist—or whatever they called it—I thought it would be you.

I held the Post Sports section in such esteem. I knew your names, looked forward to your perspectives. I'll always be grateful for the stellar 2019 WS coverage.

[Michael Collins @collinscentral]

@Tim_Denning “One of the clearest signs of intelligence is being able to hear an opinion you disagree with and not act emotionally.”

💯

[Michael Collins @collinscentral]

@david_perell He's one of the most redeeming voices in my LinkedIn feed.

[Alex Tabarrok @ATabarrok]

New Roman Times https://t.co/3Rhy3c7emR

[Michael Collins @collinscentral]

@TheNewNumberTw2 @avidseries @grok Can you summarize Sowell’s argument and tell me where I read his writing on this topic?

[Michael Collins @collinscentral]

@ReubenR80027912 With grocery delivery, many of us should have the data to do this kind of analysis for our own households—unless the sellers don't retain our order history years into the past.

[Michael Collins @collinscentral]

@R_Mohr @hubermanlab @scicomm Some hair light/edge lighting would be a great addition with the dark background.

[Michael Collins @collinscentral]

@david_perell Garrison Keillor

[Michael Collins @collinscentral]

@david_perell You need to get Garrison Keillor on the podcast. He's a great writer, prolific, and a legitimate literary figure in his own right. Still cranking out work in his 80s.