Casca, one of the Roman conspirators who assassinates Julius Caesar later that day, says it first. I stepped out of the bedroom this morning just after sunrise and said it again. A shaft of yellow sunlight, no more than two inches wide, had filtered through the budding forest, streamed into the east window of Mother’s office on the north side of the building, and squeezed through the angled door jamb onto the tiled hall floor. It was gone in a couple of minutes, but it spoke volumes: about the reliability of celestial promises, the annual defeat of seasonal affective disorder, and the certainty of sultry July days to come.

I have a feeling that we think about light and darkness a lot less than we used to not many years ago. Before rural electrification, our grandparents either burned kerosene or candles after dark or went to bed, as they said, with the chickens. A trip at night to the bathroom, whether indoor or out, could be a perilous feel-your-way adventure, with chamber pots the disagreeable alternative. Around the time of the First World War the Eveready Company began producing a fairly reliable flashlight (if you dropped one, though, the bulb blew out for sure) and bicycle headlights that made nighttime travel much less perilous. But batteries weren’t cheap yet, and during the Second World War were hard or impossible to get. Although I used to sneak the flashlight into bed to read under the covers, we kids were never allowed to play with the flashlight, a discipline that’s with me still.

Our houses now, with low-voltage energy-saving night lights and appliances and electric clocks that glow, are hardly ever really dark. Outside, there’s always light somewhere. A photo of the East Coast taken from space at night shows one great electric smear all the way from Miami to beyond Portland. Like Lady Macbeth when she begins to lose her mind, we have light always with us. The stars of our long-ago childhood are still with us, but increasingly faint; it’s not just from failing eyesight that I can no longer count the seven sisters of the Pleiades.

I have friends at both ends of the American continents who experience much more dramatic differences that we. At our location, roughly halfway between the Equator and the North Pole, we see a significant difference in daylight from winter to summer. But as our hot, sunny weather here approaches, Francesca, a lovely young tour guide we met this winter at the southern tip of South America, mentions mournfully the darkness and cold at Fin del Mundo, which, at 54 degrees south, is in May roughly the equivalent of Edmonton, Alberta, in November. She acknowledges that skiing is popular down there, particularly among visiting Europeans; but her Facebook photos show no winter sports ­ unless you count a lot of lively Chilean bistros.

At the other end of the Americas, at almost 68 degrees north, and 122 degrees removed from Francesca, is a great friend, Larry, who lives in a hand-crafted bungalow on the edge of Coronation Gulf ­ part of the old Northwest Passage ­ in the village of Kugluktuk. On clear nights Larry can read at midnight by sunlight, and within a few weeks his sun will be above the horizon around the clock. He’s built a greenhouse on the south side of his house and grows precious vegetables there long before the ice of the Coppermine River lets go, a few dozen yards from his back door. Just beyond the greenhouse he’s manufactured a little garden (you have to make your own soil north of the Arctic Circle), well fenced in against hares, caribou, and dogs. Here he grows more vegetables, including some potatoes, which he reckons cost him many times as much as if he bought the air-freighted variety at the local Coop. Kugluktuk, like many villages in Nunavut, has town-wide wireless Internet access, so naturally Larry has a blog, with pictures of his ultralight aircraft and greenhouse. As the light grows and the temperature rises, he’s keeping an eye on the river. The ice this year has jammed as high as the banks at his cabin a few miles upriver, and there’s a good chance the cabin will end up in Coronation Gulf sometime during the next month or so.

Speaking of light, Larry, having thought about it, and being so far north, once opined that a six-foot-tall human being standing at the North or South Pole would always have the sun in sight, even when it’s dark a few miles farther toward the Equator. I’m not much of a scientist, but it sounds plausible to me. Anyone care to disprove it?

As I type these words, just before sunset, the sun streams into the west window of my office, just as it did Mother’s at the other end of the day. On my desk is a little pocket calculator, maybe the size of half a deck of cards, that I’ve carried with me for at least thirty years, in my tool box or in the truck glove compartment. It has little translucent glass panels and no place to put batteries. A friend tells me it runs on light. That I don’t find plausible, but it always works.

Downstairs, the temperature of the storage tank of the solar hot water heater tells me that we can do a wash, take a shower and a bath, and do the dishes free! Well, not quite. Like Larry’s potatoes, our hot water will be a lot more expensive than oil-heated until the cost of the installation is amortized. I likely will not be alive at that point. But who cares? The silence in the cellar after a shower is delightful. So we celebrate the returning sun, and understand once again why the far-north Scandinavians yust go nuts on Midsummer Night.