I'm in Kano, northern Nigeria's biggest city, seat of another ancient emirate and a major jumping off point for the old trade routes into the Sahara. It's very hot and very dusty, with the Harmattan winds bringing sand in from the desert and turning the sky a dull brown.
Research during Ramadan is proving an exhausting experience. With the mercury nudging forty degrees, your natural inclination is to continually stop to take in fluids, but across much of the city, cafes are closed during daylight hours, and, besides, to drink publicly while the population waits patiently for the sun to drop would be grossly rude.
Instead, I've been relying on short trips darting out to hit a few hotels on the back of a motorbike taxi, and then back to where I'm staying, or over to Sabon Gari. This is a Hausa term meaning "Foreigner's Quarter", describing the area where the non-Muslim population live - Nigerians from the south. Here you can eat, drink and even buy a cold beer if the fancy strikes you, and no one bats an eyelid.
The beer issue is an important one throughout the north, and not just because sinking a cold one is a nice way to wrap up the day. In the last few years, northern Nigeria has been experimenting with the introduction of Sharia - traditional Koranic law. This has opened up serious political fault lines in the country, and riots between Christians and Muslims have been depressingly commonplace in some areas (most famously a couple of years ago when the Miss World competition was to be held in Nigeria, resulting in the deaths of several thousand in communal disturbances).
Away from the politics, life in the Kano's old city seems to be continuing as it has for hundreds of years, bar the introduction of traffic pollution. I took a tour of the traditional dye pits, where huge bolts of cloth are dyed deep indigo - the same cloth worn by the nomadic Tuareg people across the Sahara. No one knows how long this trade has been going on - the pits I visited had been on the same site for over 500 years, but the practice is undoubtedly more ancient than that.
After the bustle of modern Nigeria, it is exciting to be somewhere that ties into older ways of doing things. From Kano, camel caravans used to head north into what is now Niger, and to the Mediterranean, or east across Sudan to Cairo or the Red Sea. The souqs of Marrakech and Fes in Morocco, to the west, were directly linked to Kano before the modern obsession with visas and passports.
This is my penultimate entry in this journal. In the next few days I'll be heading on to the border to cross back into Cameroon. It'll be sad to leave Nigeria, which has never failed to surprise, but there's still some way on the road before this research trip is complete.
For now, I'm heading off to find a much-needed cold drink.