Just a few.

• Brainteaser.  There’s a worked solution to the one in my April Diary here. 

• Anti-drone technology.  From a listener to my March 22nd podcast (yes, I am way behind—sorry!).

Mr. Derbyshire: I was listening to your most recent RadioDerb Podcast. In one segment you talked about President Trump consulting with someone who has some knowledge of anti-drone technology—”if there is any.”

Well, there is: Epirus, Inc. based out of Southern California. They are developing electronic pulse technology that can be fired at drones and then disable them.

An Epirus was a type of bow in Greek mythology that just automatically fired arrows. It did not have to be reloaded. In theory, from the way I understand it, these electronic pulses can basically be fired in the same way—in an almost infinite amount.

Thank you, Sir.  No half-hour browse of X is complete nowadays without some seriously scary video clip of drone swarms. I'm glad to know our military-tech people are on the case. 

•  Islamic misogyny.  In the April 26th podcast I observed that 

Islam in all generality is misogynistic, and seems always to have been. The 19th-century Islamophile Sir Richard Burton reported that a pious Muslim man, in his prayers, thanks God that he was not born a woman.

An Israeli friend responded: 

In fairness, I should admit that Jewish prayers also contain a blessing praising God for not having made one a woman. But it's clear from the context that this is a prayer stating *differences*, not superiority. There are even some forms of the Jewish prayer book—old ones—in which women thank God for not having made them a man.

Thank you, Sir.  I recall reading something long, long ago in which the writer tried to distinguish between ”masculine” and ”feminine” religions or styles of religion.  Judaism and Islam are ”masculine,” Buddhism and Roman Catholicism are ”feminine,” Protestant Christianity is ”masculine,” and so on.  I can't remember the details of the argument, but there may be something there. Didn't one of the Romans describe early Christianity as a religion of ”women and slaves”?  Cue Fred Nietzsche…  

•  Cuyahoga.  Concerning the trip to Cleveland I recorded in my April Diary. 

Reader A:

I can understand your being underwhelmed with the Cuyahoga Valley National Park. Its focus really is (or should be) on the Ohio & Erie Canal. CVNP and the Cleveland Metropark system overlap along the canal. I do a lot of my bicycling on the towpath trail that is alongside the remnants of the canal. The trail starts in downtown Cleveland and reportedly runs a hundred or so miles south. Someday I hope to cycle the entire length. 
 
Next time you're in Cleveland, consider a visit to the Garfield Memorial in Lakeview Cemetery. It's a gorgeous tomb/building for the former US president.

Reader B:

Don't waste time with any national parks east of the Rockies.  The eastern parks are lame.  Go west, young man.

—Yellowstone.  Avoid the Yellowstone crowds and go around opening day, mid April.  Barely any tourists.  The roads are slow going due to the bison traffic jams.  Some snow but if you're day tripping, it's not a bother.

—Any of the many National Parks in my home state of Washington (Olympic, North Cascades, Gifford Pinchot), but the Big Kahuna is Mt Rainier.  Go in August or September when the likelihood of sunny days is higher.  (Mt Rainier gets something like 200 inches of precipitation yearly).  That time of year the mountain meadows are in bloom.  If you are energetic enough you can get close to Camp Muir and back in one day.   Really nothing else like Mt Rainier on a sunny late summer day.  Magical.  

—Zions in Utah.  Magnificent rock formations, lots of altitude variation, high aspen laced meadows and deep canyons.  Hard to pick the right season. Snow can arrive as early as September.  I'd probably go late summer/early fall when school is back in session and you have a chance to see the quakies turn color (a window of about a week).  Schlep over to nearby Orderville for some Mormon history while you're there.

Thanks to both.  It was just a flying visit to see the solar eclipse.  I wish we could have spent more time in Cleveland but Mrs. Derbyshire is husbanding her vacation days.