Salting the earth

Humans have fought bugs since the dawn of civilization, and while we’ve dramatically improved our ability to wage chemical warfare, we still do close-quarters battle with melee weapons. The Bug-A-Salt changes all that.

Millenia of human innovation culminated in this, the pneumatic salt-firing shotgun. It alters the world’s balance of power, and with great power comes a great question: “Is it safe to shoot near potted plants?”

Be aware of what’s beyond your target, said Beth. If it’s a tiny herb garden, recall the phrase, “salting the earth.” Legend has it that ancient conquerors practiced scorched-earth tactics by sprinkling salt on enemy fields.

“Surely,” said I, “that’s just symbolic.” Salt is a rock. To become an herbicide, wouldn’t it take a huge quantity? In the age when fly swatters were still new technology, salt was relatively precious. Wouldn’t that be wasteful?

This begged for an experiment. First, we’d need a plant to test, something that grows reasonably fast and indoors so we could control the weather. Wheatgrass fit the bill, so we ordered a growing kit advertised as “ready to eat in 7 to 10 days.” Apparently wheatgrass is sold as food (for humans).

The kit came with four separate tubs, each with a pre-measured seed and soil quantity. Intending to control for variations in sunlight and other conditions, we distributed the soil and seeds from one of the four into an egg carton. Of the carton’s twelve cups, four egg cups received no salt, four received a sprinkling, and four received a heavy salt coat.

Likewise, the remaining three manufacturer-supplied supplied containers received received no salt, a sprinkling and heavy salt. We call “lightly salted” about the heaviest amount you might reasonably call “sprinkling.” The heavy amount was outrageous, enough that we will later see salt deposits climb the walls of its container, presumably thanks to evaporation and capillary action.

Three containers showing amount of salt
Before planting

We watered every three days and recorded growth. I expected we would need to do something tedious like count the blades of grass in each container, but the difference couldn’t have been more stark.

Control grew about an inch. Of the salted, only postsalted sprouted at all.
Day 4

In the egg carton, we salted the second column lightly and the third column heavily, repeating the pattern for the remaining six cups not shown. We salted the front row (presalted) before planting, and the back row (postsalted) when the seeds had sprouted, three days after planting.

The presalted egg cups never sprouted, and the postsalted cups withered dramatically. Even grass in unsalted cups adjacent to salted cups struggled, particularly one that I accidentally splashed while watering its salted neighbor.

Nearest cups, particularly on the left are unsalted, but grass is much shorter than control in background
Cups nearest and furthest from the camera are unsalted

None of the salted egg cups ever grew, but the lightly salted tub did manage to sprout on day 9. At first only a handful of sprouts appeared, but more followed for the next several days. By day 15, some of the hardier blades were catching up to their unsalted brethren.

Lots of grass in the unsalted tub, sparse grass in the lightly salted tub
Day 15

Despite its valiant effort, however, the salted grass remained sparse. We stopped the experiment on day 26.

While not that fabled “nothing will ever grow again” effect, it looks like a sprinkling of salt could cause devastating famine. In this experiment, we used about a teaspoon of salt on the lightly salted 3 3/4 inch square container. A 3 pound box of Morton’s kosher salt comes in a 90 cubic-inch box, so this works out to a little more than an ounce and a half of salt per square foot. The egg cup spillover suggests that a smaller amount could still be effective, so we’ll round down to 1 ounce per square foot.

Knowing this, how much salt will we need to starve our enemies if we aspired to warlording? We might decide to make a name for ourselves by sacking Carthage, with its population of 700 thousand, according to Strabo XVII Ch.3§15. According to Wikipedia, The Economics of Agriculture on Roman Imperial Estates in North Africa estimates that a family of six needed 7 to 12 acres of farmland to feed itself. Thus, at 2 acres of Carthagian farmland per person, we need to cover 1.4 million acres. If planted nearby, this would surround the city for some 30 miles in all directions and we would need about two million tons of salt to cover it.

We can use Emperor Diocletian’s Edict on Maximum Prices to put this in perspective. The edict listed salt at 100 Denarii per modius, a volume of around 530 cubic inches. Using our previous density estimate of 30 cubic inches per pound, this works out to 6 Denarii per pound or 12 thousand per ton. Since the edict was an attempt at price control, it’s safe to say that commodities it listed actually cost more, so a ton of salt might have cost about the same as a soldier’s annual wage. Cost-conscious generals would suggest using our two million ton salt fund to hire a gargantuan army instead, a million strong. With various sites estimating the Roman force that actually destroyed Carthage at 80 thousand infantry, our salt budget could scale it up by an order of magnitude.

Even using enslaved Carthagians to harvest and sprinkle, salting doesn’t look practical, but today’s budding emperor can take heart that Alibaba has road salt priced at a mere $100 per ton. On the other hand, today we have much more effective herbicides, so we don’t need to salt enemy fields. The important question, however, remains: will our potted plants become casualties of Bug-A-Salt conflict?

Suppose we have a planter that covers one square foot. The Bug-A-Salt’s magazine holds about a tablespoon of salt, good for 50 or so shots. Our ratio of 1 teaspoon per 14 square inches works out to 10 teaspoons per square foot, or three full Bug-A-Salt magazines per plant. Thus, if we kill 150 flies on our plant we would do collateral damage equivalent to this high, if not total, wheatgrass kill rate:

Bushy control beside sparse lightly-salted tub
Day 26

The Trouble With Stack Overflow

More and more, searching for how to do one thing or another leads me to question and answer site Stack Overflow. This is good in many ways, especially because Stack Overflow’s open format allows anyone to read full answers, obliterating closed systems like Experts Exchange that used to clutter Google results but refused to actually give you the answer without registration.

Lemming that I am, I signed up. Not thanks to an altruistic desire to make the Internet a better place by helping others, nor to get my own questions answered. Stack Overflow has grown to a critical mass where enough employers and peers might know it to conceivably consult your reputation on the site as a signal of competence.

Many talent markets suffer from asymmetric information. Computer programming productivity studies find order of magnitude differences between the best and the worst talent but no corresponding difference exists in pay, which ranges only from $54 thousand to $104 thousand for averages of groups from lowest to highest seniority. Taking on faith the intuition that this represents a market failure and therefore inefficiency, Stack Overflow’s token economy for reputation points that track the user’s talent looks promising as a potentially more efficient signaling solution.

The economic idea of “signaling” refers to sending a message by choosing a costly action. I signal when I buy my wife flowers on Valentine’s Day; I am not convinced she needs the blossoms in mid-February. I am sorry to say this to all you cheapskates out there, but the cost of signaling is the entire point. A fancy diamond ring goes further than flowers…

Love cannot be measured scientifically or directly, at least not until neuroscience dramatically advances. We must instead show other people all the time that we love them, and that means we look to send the right signals.

Just as in the market for love, the market for programmers could benefit from signals. The signalers’ main real cost is time, but the tokens of Stack Overflow’s economy are questions questions, answers and votes. Successfully bartering questions and answers into votes builds reputation.

Judging by the number of answers that now appear prominently in Google results, this makes a very successful business. But after only a short stint of use, I will heavily discount Stack Overflow reputation as a proxy for talent because of what users call the “Fastest Gun in the West” problem:

If a person sits down and answers a question in a long, thorough way, going through every nook and cranny, once they post their answer, it will already be one of about seven different ones, some of which have already been upmodded. This wouldn’t be a problem if those answers were as thorough as the one this guy’s posting, but they usually aren’t. Some of them are downright wrong, some aren’t even answers to the question.

I personally observed this when answering a Java homework question:

I’m trying to count the number of characters that occur in a java string. For example: given the poker hand 6s/3d/2H/13c/Ad
how many times does the / character occur? = 4

That question received three answers before mine. All three were wrong. That’s right. Ask, “how to count the number of a specific character in a string,” and three users with respectable reputation respond incorrectly.

This is not likely to change since Jeff Atwood and others agree with legitimate reasons for encouraging many rapid answers. They say there is no problem because “getting rapid answers the entire goal of a question and answer site.” For some purposes, however, there is a problem. For signaling talent, writing a blog and developing an online code portfolio is still a better option.

Death To the Downloaders

Paint.Net is a well-known free photo editor. It may be an excellent product but I cannot recommend it because only an alert and somewhat savvy user can navigate its website to find the actual homepage screenshot The home page sidebar looks like advertisement, so that big blue button looks like right place to click.

Nope. That installs Pdf Creator and its pile of adware.

Once you figure out the most prominent item on the page actually contains adware, your next likely target becomes the big green button.

Wrong again. This time you get Zoom Downloader.

Think about downloaders for a moment. When computers were made from bamboo and ran Netscape 1.0, downloaders may actually have added useful functionality to a browser. In 2012, they have been pointless for at least ten years but hapless Internet users still confront them constantly.

In the spirit of not ascribing to malice what incompetence can explain, some of these downloaders are pet projects, done only because they are easy, solving problems that don’t exist and creating new ones.

If you did upgrade to the latest version of Flash from the Adobe website, you very likely have Adobe Download Manager installed.

What is the Adobe Download Manager? “The Adobe Download Manager (Adobe DLM) is a small application that is used to deliver two of Adobe’s most frequently downloaded products, Adobe Reader and Adobe Flash Player.”

Is the Adobe DLM safe to use? According to Adobe: “The Adobe DLM is signed by Adobe, uses SSL, MD5 checksum integrity verification, encryption and other methods to insure that the software you request is the software you receive from Adobe.”
Pay attention to the bold part of the last sentence. The reason I marked this part of the sentence is that apparently you can force automatic download and installation of software upon anyone who visit your website and have Adobe Download Manager installed [CVE-2010-0189]. Safe to use, ha?

Download managers by definition require firewall openings and not all downloader creators are as stupidly benign. They produce software you do not need. They trick you into installing them.

Aunt Millie, of course, realizes none of this; she just wants to remove red-eye from her cat pictures. By now utterly baffled that she cannot get Paint.Net to install, if she can find her way back to its site with her now crippled browser and locate the small download link, she tries again. Paint.Net download page screenshot This time she gets one step closer, the actual download page, with another big blue download button.

Fool me thrice. Another download manager.

On fully patched and otherwise completely clean Windows Xp, I took before and after screenshots. Internet Explorer froze once and was so broken after the second install that I could not download the third craplet. Something along the way disabled Windows Firewall.

Ideally, when someone clicks those ads, the browser would interrupt with, “Awesome Downloader Express from Trojans R Us is not the software you want. Try instead,” a stillborn scheme due to implementation difficulty. Gray-hat warring with distributed spiders that drive up click and bandwidth costs might at least be more fun. I am not sure my vigilante altruism goes that far, but if I find someone waging that campaign, I will applaud them.

So the best I can do for poor aunt Millie is rage. From one remote corner of the Web, the futile scream goes out, “Paint.Net, you may be a fine program, but I cannot support you.”