Because I don't own a working vehicle, I have to hike into town (five miles) to carry my outgoing mail to the post office, pick up my packages, and then hike (another five miles) back home. Often I'm under heavy load both ways. However, as a side benefit, I get to eat ice cream sandwiches and Hunt Brothers Pizza while I'm in town. Anyway, it is to my advantage to have a good backpack and a spacious cross-body carry bag.

Yes, there once was a time when backpacking ten miles felt like nothing and I could do it every day. But I'm an old guy now, and I've slowed down a bit due to wear and tear. You wait long enough, and it'll happen to you too.

A warning to buyers of backpacks and carry bags: These don't really hold as much as their sellers or manufacturers claim. The actual capacity is usually about

*half* of the advertised capacity, if you carry the full bag with all zippers closed.

I've been buying backpacks and messenger bags experimentally from sellers on eBay and on Amazon. Here are some that have found favor with me — plus a few more that didn't.

Careful observation and repeated measurements has taught me that packaged, roasted coffee beans have a volume of 58 cubic inches (or 0.95 liters) per pound. It has become my main method for measuring bag volume. I have on hand packages of various coffees in one-pound, two-pound, and five-pound sizes. They allow me to pack nearly any backpack or carry bag to fullness without leaving any significant gaps of empty space.

**BACKPACKS**1.

Hynes Eagle 40L. This has been my workhorse for a while. It's big enough to hold six pairs of men's size XXL jeans in the main compartment, and still get the zipper closed. It will, alternatively, hold 18 pounds of packaged coffee beans, if the packing is optimized so that no space is wasted, and then the zipper will barely close, so the main compartment of the Hynes Eagle 40L is actually closer to 17 liters. In addition to that capacity, the backpack will carry a bit more in a secondary compartment. And there is a small tertiary compartment in which I keep letters that actually do need reading, a Pak-Lite LED cap on a 9V battery, a handkerchief, a folded up laundry bag, a chronometer-clock like what track coaches use, and a small billfold/change-purse kind of thingy. This backpack might have about 20 liters of volume capacity altogether.

2.

Hynes Eagle 44L. I don't know what idiot thinks that this backpack will hold 44 liters, but my own efforts managed to cram 10 pounds of coffee beans, having a volume of nine and a half liters, into the main compartment and have the zipper close. Clever packing tricks might allow for 12 liters of carrying capacity, maybe, and I haven't checked the secondary compartments yet. But it's clear to me that the so-called 44L backpack is even less roomy than the 40L model.

**CROSS BODY CARRYING BAGS (messenger, satchel, duffle)**1.

Ahmik Classic/Vintage Canvas Messenger Bag. The interior of the bag is well constructed, is finished, is well organized. As a decoration, the bag sports some writing that is obviously intended to mimic some official stamping by a careless army supply sergeant. It's nonsense, but it does make the bag look a little more macho. Capacity of main compartment with zipper closed: 8.5 liters. Capacity of main compartment with zipper open: 10 liters.

2.

Rapiddominance Classic Military Messenger Bag. The interior of the bag is lined with polyester, and there is a polyester flap with a plastic zippered pocket. When you remove this lining, you'll find that the bag stitching is unfinished in the interior of the main compartment (strings). Capacity of main compartment with zipper closed: 9 liters. Capacity of main compartment with zipper open: 10.5 liters.

3.

Lifewit 17" Men's Messenger Bag. This is a good little satchel. It is lined with something better than polyester, but I'm not sure what the lining material is. Capacity of the main compartment with zipper closed: 9.5 liters. Capacity of the main compartment with zipper open: 11 liters.

4. J World New York Thomas Messenger Bag. This bag is obviously too small and isn't macho enough to be carried by men. When it arrived in the mail, I laughed at it. The interior has a divider that, really, it should not have. Capacity of the main compartment with zipper closed: 7.5 liters. Capacity of the main compartment with zipper open: 10 liters.

5.

Plambag Duffle Bag 50L. This is a

*duffle* bag, not a messenger bag. Duffles are the next higher order volume capacity in manly luggage. The main compartment of this duffle bag has a compact configuration and an expanded configuration, which can be adjusted by opening or closing a zipper on either end of the bag. Capacity of main compartment with end zippers closed: 18 liters. Capacity of main compartment with end zippers open: 22 liters. Capacity of each of the two end compartments: 2 liters. Capacity of the frontal compartment: 1 liter. Maximum capacity of the Plambag Duffle Bag observed during testing: 27 liters.

*UPDATE, 20 September 2019:* I found a way to put 26 liters into the main compartment with the end zippers closed, which raises my estimate of the Plambag duffle's total capacity (including all secondary compartments) to 35 liters.

This image of a shopping bag is here for decorative purposes only.

The decorative shopping bag will hold 15 liters' worth of groceries.