Classic Chord #21 – Diabolus in musica

Strictly speaking this classic chord isn’t a chord at all, it’s an interval, the gap between just two notes rather than at least three different notes played together. The interval in question is often described in Western music as “dissonant” and perhaps because of the beating of the harmonics of the two notes against each other (constructive and destructive interference) it has been various labelled the devil’s interval, or more archaically, diabolus in musica. Moreover, it’s often been banned and at the very least lambasted over the centuries in many different realms of music.

The devil’s interval is two bits of what technically we refer to as a tritone. A jump from a root note, up a whole tone and then up a whole tone again, so F to G, G to A, and finally A to B. The leap from F to B is quite dissonant.

In the right hands, it can add an electric frisson to a piece of music. Think of the intro to the Rush instrumental YYZ from the 1981 Moving Pictures album. The guitar pattern played staccato in 5/4 time oscillates between F# and C (the tritone being F#-G#, G#-A#, A#-C) and represents the Morse Code for YYZ (Toronto Airport’s call sign). Similarly, the Blue Oyster Cult song Workshop of the Telescopes from their eponymous 1972 debut album, uses the devil’s interval A-D#.

Although odd, almost occult, importance has been attached to this interval, fundamentally (pardon the pun), it’s just an augmented fourth or a diminished fifth. Picture the scale of C major:

C  D  E  F  G  A  B  C
First note (the root) is C, the fourth note is F. If you augment or sharpen that you get F#. Similarly, flatten or diminish, the fifth note in the scale, the G and you also get F#. C-D, D-E, E-F# – the tritone. Works the same for any major scale. Of course, there is a natural tritone in the scale of C major, but only one: F-G, G-A, A-B, same for whatever major key. In a harmonic context the tritone sets up a certain feeling, that F# to C in YYZ, is just an arpeggiated fragment of a D dominant seventh chord, a D7 – D-F#-A-C.

Where would rock and blues be without the 7ths (which of course are flat relative to the major scale. Look at CDEFGABC again, 7th note would be a B, but it’s down a semitone, so flat, in the (dominant) 7th. In the chor of C major 7, it stays as a B and has a much softer, almost summery sound, relative to the grittier dominant 7th with its devil’s interval.

Rush use the clash of a tritone in several songs, the intro to Between the Wheels has one with a F#11 chord resolving to an Am (both have a D note in the bass, so they’re more correctly, Dm13 and Am(add4), respectively.

Neither Rush nor BOC were being original in using this interval it had been around music for centuries, stirring passions and summoning the devil. Wikipedia has more details and more examples from musical history. In pop and rock music George Harrison uses tritones on the downbeats of the opening phrases of The Beatles’ songs “The Inner Light”, “Blue Jay Way” and “Within You Without You”, to create musical suspense resolution and of course, the opening riff of that most classic of heavy rock songs, Jimi Hendrix’s Purple Haze uses the very same interval before leaping into the Hendrix Chord (Classic Chord #3).

Oh, almost forgot, here’s the interval in action, with me playing a version of the YYZ intro:

Forget twitters, we want warblers

Over the last few months I’ve got to learn a little about the birds we call warblers. It was always a joke between Mrs Sciencebase and myself, if we heard a tweet we didn’t recognise one of us would proclaim “warbler!” and we’d move on…

Well, it turns out that a lot of the time we were right without knowing it. I’ve snapped a few of them and we’ve definitely heard the grasshopper warbler (at RSPB Folwmere) but don’t think we’ve seen it.

Cetti’s warbler – WWT Welney

Sedge warbler – RSPB North Warren, Fen Drayton Lakes, Ouse Washes

Reed warbler – RSPB Fen Drayton, Ouse Washes

Common whitethroat – RSPB Bempton Cliffs, South Cambs

Lesser whitethroat – Rampton, S Cambs

Blackcap – RSPB Minsmere, Rampton, Cottenham, elsewhere

Willow warbler – Rampton, Cottenham, elsewhere

Chiffchaff – See and hear almost everywhere there are trees

Grasshopper warbler – possibly heard at RSPB Fowlmere and Overhall Grove

Marsh warbler – yet to positively ID, very rare, 2-3 breeding pairs in UK

Wood warbler – Photographed in Croatia

Dartford warbler – Seen but not photographed at RSPB Minsmere

Moustached warbler- yet to positively ID

Sardinian warbler – ditto

Savi’s warbler – ditto

Sub-alpine warbler – ditto

Bonelli’s warbler – ditto

Great reed warbler – ditto

Garden warbler – ditto

Pallas’s warbler – ditto

Yellow-browed warbler – ditto

Icterine warbler – ditto

Melodious warbler – ditto

Barred warbler – ditto

Fan-tailed warbler – ditto


The term warbler applies to some distinct species as you can see, it’s more of an umbrella term for perching (passerine) birds that share characteristics, such as being fairly small, vocal, and insectivorous.

As sure as eggs is eggs

The shape of a bird’s eggs depends on how it flies, according to new scientific results. Sleek birds adapted to streamlined flight tend to lay more elliptical and asymmetric eggs, according to new research published today. The work cuckolds the classic theories about egg shape.

Broadly speaking, birds’ eggs can be ball shaped or elongated ovals. They can have one pointy end or be very symmetrical. Diet, nest space, cliff dwelling and other factors have all been scrambled to explain why some eggs are one shape and others another. Now, Joseph Tobias from Imperial College London, writing in the journal Science explains how he and his colleagues have measured the shapes of almost 50,000 eggs of 1,400 bird species. They analysed this hard-boiled data in the context of the bird family tree and species characteristics, such as nest type, clutch size, diet, and flight ability.

The researchers discovered there was a correlation between strong fliers and more elliptical and asymmetric eggs

The team found that murres, aka guillemots, (pictured above, prepping some eggs) which are fast, direct flyers that can also dive deep underwater had some of the most asymmetric eggs in the study. This was previously thought to be about precluding the egg rolling off a cliff edge into the sea below; an over easy theory. By contrast, owls – built for light, gliding flight – had some of the most spherical eggs, although the barn owls eggs are rarely sunny side up as it’s a dusk/night hunter.

“Bird eggs – previously described as ‘a miracle of packaging’ and ‘the most perfect thing in the universe’ – have fascinated people for millennia, yet only now are biologists beginning to crack the mystery of what makes some eggs more ‘egg-shaped’ than others,” says Tobias.

Lead author on the paper Mary Caswell Stoddard of Princeton University, adds: “In contrast to classic hypotheses, we discovered that flight may influence egg shape. Birds that are good fliers tend to lay asymmetric or elliptical eggs.”

The most obvious reason for this adaptation is simply that the sleeker fliers have less room in their abdomens and narrower oviducts for spheroidal  eggs. So, it’s a packaging problem for mother birds.

There’s no poaching of theories here, Tobias says that his team “found no support for the traditional ideas that variation in egg shape is caused by nest structure or placement on perilous cliff ledges, and instead found that egg size was related to the amount of calcium in the diet, and egg shape was best predicted by adaptations for powerful flight.”

Remember, if you don’t speak French one egg is never un oeuf

“Avian egg shape: form, function and evolution” by M. C. Stoddard, E. H. Yong, D. Akkaynak, C. Sheard, J. A. Tobias, and L. Mahadevan, Science, (2017).

Western yellow wagtail (Motacilla flava)

It’s so easy to be distracted, especially when it’s 30 degrees Celsius in the shade, and you’re flagging after a long-winded drive to a reserve (today RSPB Ouse Washes at Welches Dam near Manea in Cambridgeshire). There seemed to be a reed bunting every 30 metres in the reeds along the waterway behind the flood bank and bird hides. There were a lot of barn swallows and a lot of sedge warblers and reed warblers.

The RSPB members’ book suggests there are some 13 different warbler species seen on the site, so when I saw this beautiful creature I leapt to the assumption that it was some kind of warbler…as ever it took my virtual ornithological mentor to correct my misconception – yellow wagtail (Motacilla flava). It’s a juvenile though hence the muted colours.

I must add though that I’d seen on on a post on the washes side of the flood bank close to some lapwings and had thought it looked like a wagtail. But, it was a long way off and on a hot and hazy day no zoom lens is going to correct for refractive abberations due to turbulent hot air rising.

Anyway, yellow wagtail it is, another one for the gallery.

Yet more woodpeckers

Back at the end of February I spotted a woodpecker high in a tree in our local woodland; great spotted woodpecker (Dendrocopos major). Of course, for me, woodpeckers are more often heard and not seen, the headbanging of this species and the mocking laughter of the green woodpecker or yaffle (Picus viridis). As the weeks went by there was more mocking laughter in the woods as if the yaffles were scoffing at the fact that I couldn’t get a shot at them. I caught one in flight elsewhere, but then gave up on trying to get a photo of greens having spotted a GSWP heading in and out of a high hole in a tree.

Eventually, I saw a chick, saw it grow, saw both parents (Dad with his red nape, Mother with her completely black and white upper body). Coming and going, bring caterpillars and beetles and taking away faecal sacs. Seems there was only one chick to nurture, whereas there are, it seems, usually half a dozen. Anyway, when it fledged, I missed the departure, but did see what looked like a mini-me GSWP a few days later. That was the end of May.

Now, a few weeks later, there’s a lot of noise in a different part of the woodland, holes in trees and the occasional sighting of a green woodpecker chick, and another out of the hole, and then the next morning three or four calling in yet another location. No adults seem to be around, although the books say they do continue to feed them for a couple of weeks after fledging. It’s intriguing. Where are the adults? Do they simply stay away until humans and canines are gone, but if they’re so shy, why do the chicks make such a lot of noise and remain fairly obvious in some of the trees?

The day-flying Cinnabar moth

The Cinnabar moth (Tyria jacobaeae) can be found throughout Britain, anywhere that its larval foodplants, ragwort and groundsel grow, except northern Scotland. Indeed, the species was introduced into New Zealand, Australia and North America to control poisonous ragwort.

The Cinnabar, flew to actinic light moth trap at night, surprisingly.

The moth is named for the red mineral cinnabar, mercury sulfide, because of the red patches on its predominantly black forewings and its hindwings , edged with black. Like many other brightly coloured moths, it is unpalatable to its would-be predators.

Cinnabar moth

Top Ten Pop Cameo Appearances

There are plenty of actors who try their luck as musicians and lots of musicians who do the reverse. Some of them start out as wannabe actors and end up as musicians and vice verse. And, then there are those who just fancied a cameo appearance in a pop video for the lulz.

10 Christopher Walken dancing to Fat Boy Slim’s Weapon of Choice

9 Chevy Chase lip-syncing Paul Simon’s You can call me Al

8 Hugh Laurie reprising his Blackadder Prince Regent role for the Annie Lennox song Walking on Broken Glass although the premise looks a lot like the film – Dangerous Liaisons.

7 Actor Rupert Grint playing an Ed Sheeran doppelganger in the video for Sheeran’s song Lego House

6 Sacha Baron Cohen, in the guise of Ali G, as the driver/DJ in Madonna’s 雷竞技官网

5 Godfather Part II Actor Danny Aiello playing the father in Madonna’s Papa Don’t Preach

4 Actor Courteney Cox being invited to dance on stage with Bruce Springsteen in the video for Dancing in the Dark as if she were just some random member of the public at one of his concerts.

3 DJ (not an actor) John Peel pretending to play mandolin for Rod Stewart’s Top of the Pops appearance miming to Maggie May it was actually Geordie boy Ray Jackson from the band Lindisfarne who played the instrument on the record.

2 Composer Hans Zimmer in the video for The Buggles’ Video Killed the Radio Star. Of course, it was Geoff Downes who played keys on the recording, which interestingly was the second attempt by the team to have a hit, it having been released as a single earlier by co-writer Bruce Woolley with his band The Camera Club (Thomas Dolby on keyboards for that version, which brings us to our number one).

1 Scientist and 1970s TV presenter Magnus Pyke backing vocals for Thomas Dolby’s She Blinded Me With Science

A quarter of a million gannets

As children, if my sister Sue and I were eating particularly enthusiastically, our Dad would often refer to us as a couple of gannets. I therefore grew up assuming that these seabirds were voracious consumers of sausage rolls and butterfly cakes. They’re not, obviously, their staple diet is fish and rather than eating like pigs, as it were, they are quite graceful divers who plunge into the sea to take their submarine prey.

The name gannet is derived from Old English ganot meaning “strong or masculine”, and that word in turns comes from the same Old Germanic root as our word for a male goose “gander”. Both male and female have some interesting adaptations for their seafood diet. Primarily, they do not possess external nostrils. Instead their nostrils are inside the mouth. Secondly their face and chest is lined with air sacs that act like bubble wrap to cushion the impact when they dive into the water. Their quite prominent eyes are positioned well forward on the face for binocular vision, which allows them to judge distances accurately.

I suspect that the lenses in their eyes either correct for refraction across the air-water boundary or else their brains carry a neural network that calculates the necessary correction as they dive into the water so that they know where the fish they’re targeting actually are rather than where they appear to be from the bird’s eye view in the air above.

The birds photographed here are just a few of the quarter of a million or more nesting on the beautiful but smelly and noisy Bempton Cliffs on the North Sea coast of the East Riding of Yorkshire, England.

Northern marsh orchid, Dactylorhiza purpurella

When visiting RSPB Bempton Cliffs on the coast of the East Riding of Yorkshire to see the puffins, gannets, razorbills, guillemots and kittiwakes, don’t miss sight of the northern marsh orchid, Dactylorhiza purpurella.

According to the Kew Gardens website:

Northern marsh orchid occurs throughout the northwestern part of Europe. It is found in southwestern Norway, southern Sweden, Denmark (including the Faroe Islands) and the UK. In the UK it is widespread in northern England, Northern Ireland, Scotland (including the Shetland Islands) and Wales. It is found at up to 600 metres above sea level.

Don’t call Saul, call Dexter

The forensic luminol blood test familiar to CSI and Dexter fans alike can be used to illuminate blood stains. It uses peroxide which reacts with the iron in haemoglobin. However, 20+ years ago scientists realised that the same test could be used to detect peroxides too. Indeed, researchers worked out that they could use the luminol test to prove that a pharmaeutical product claiming to contain the antimalarial drug artemesinin (a natural peroxide) actually contained this drug and so help avoid pharma fraud.
Now, a team in China has turned that idea on its head and are using the antimalarial drug itself to give the luminol test a 100,000 times sensitive boost that also makes it more specific to identifying blood stains and distinguishing them from other dark stains one might find at a crime scene investigation. Better call Dexter…
My latest news story on this work appears in the magazine Chemistry World.