Fixing the broken Periodic Table for the  world of Chemistry.



Jim & Rhoda Morris  ( A physicist & Chemist team)
What was the world of chemistry  and the periodic table like  when
Henry Gwyn Jeffreys Moseley, a physics graduate student was looking around for a project to do for his advanced degree in physics?

Well The world of chemistry was a poorly organized muck of negatively and positively charged maybe particles.

At the same time while your searching  with us look and find if you can find some glimpse scatter through out this note, high lighting how science and scientists work together to the benefit of all!.  If the message comes through can you guess Why the proven productive rate of science is so much greater than other professions. Why in the end and in spite of  all of the obstacles, that some would throw in science's  path, it over comes them and keeps moving on  at a faster rate. Can we use science's  secrets in other professions?
A National Science Foundation ...NSF ... funded  video project titled the Mystery of Matter.

The expressions  and or errors in this note are solely those of the authors and not those of the sponsors.
 

WHAT WERE SOME OF THE HOTTEST QUESTIONS IN PHYSICS AND CHEMISTRY  THAT NEEDED TO BE SOLVED?
WHAT WAS AN ATOM MADE OF? 
WHAT DID AN ATOM LOOK LIKE?    
WHAT WERE  THE CORRECT ADDRESSES FOR  ALL THE ATOM'S ... in the period table?         ...
WAS  THERE PROOF OF MISSING ATOMS?  
WHICH OF THE  NEW THEORIES ABOUT ATOMS  WAS THE CORRECT ONE?
WERE THERE NEW INSTRUMENTS TO MEASURE AND ANSWER THESE QUESTIONS?
WHO WAS  WORKING  OR AVAILABLE TO WORK ON THESE PROBLEMS?
In England some of the very active scientists  were working  on the questions above.  They  all came away with awards.  They all worked well together competitively and individually to get it  right. All scientist have to do this or they will simply get passed by those who do.

Here is a small sample of the motley crew that Henry had to deal with. They were all as  sharp as a tack and go getters.

Professor Lord Rutherford of Nelson author of a number of models of atoms  encouraged   Moseley experimental work on the atom


William L. Bragg X-ray crystallographer, co discoverer (with his Professor father 1912)   of the Bragg law of X-ray diffraction which Moseley  depended on and used  in his experiment.

Meet mister  Planetary Model of a hydrogen atom suggested by Bohr.
The single orbit  shown above is just one of an infinite number circular paths single electron can take.  available. The one  proton  can be lots of proton s

Niels Henrik David Bohr an almost student corresponding  and encouraged  Moseley about  his work on the .atom which would  experimentally confirm his theoretical  work.

MORE

AND

THERE

WERE


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The authors, discovered during this project, a  pleasant and surprising technical connection  between us (Jim and Rhoda) and  the scientists above. For several years we studying theoretically and experimentally the broadening of spectral lines such as
hydrogen and heavier atoms that are under high pressures similar to stellar atmospheres and a-bombs blasts. Here is a working example of the step by step progress all scientist share in. There are no one man stands the giant of all giants. No matter what one has been told and believes iit  beyond all reason.

Theoretician  can  and do build great theoretical worlds which are internally consistent  within themselves but until they are experimentally verified several ways they are pure conjecture and debate  and have fun but don't take them even a little bit true.

 


Make sure that the picture includes that we made the unit

spectroscopic the same curious incidence showing how science works that the authors had also worked a few years ago on the hydrogen spectra,  in particular the Beta line of Hydrogen. We were also checking theory, JUST like Moseley,  in our case we were testing for the spectral line shape and  line width of the  Beta line in the visible spectra which  was caused by the interaction of the free electrons surrounding and disturbing hydrogen atoms while they are radiating. Our worked was supported by the NASA/ Air Force  funded contract. Just like Moseley we also used a grating In our spectrograph. But very important Moseley used a very special grating, one made by nature. it was in crystalline form. It had just had been discovered  and worked on by in neighboring facilities by the Bragg's.
 

Below is one of many photos we took of Moseley's equipment while visiting the Oxford   Museum in Oxford England. Our purpose was  to study the  original equipment Moseley  used in his ground breaking work on the atom.  From experience we felt the compelling need to get our information, not just  from the professional historians, but also first hand from an experienced  experimental physicist and a chemist's point of view ... We did this to accurately replicate Moseley equipment ...and his  experimental technique, and to share this for the NSF project.


Hint, hint to be noted we asked others  including the then National Bureau of Standards to repeat our experiment, as is done, in all good science. They and others did and concurred that our work was correct.

Our experiment was part of a much large body of work. It was titled ( Experimental Test of H Beta Stark Broadening Theory at High Electron Densities J. C. Morris and R. U. Krey, Aug 19,1968 Physical Review Letters Vol. 21 Number 15 Physical Review Letters.

 Back to the story and very important photo showing something very important, more important than who did it.


For the photo below is one of a number of  the actual Potassium Ferrocyanide crystals that Moseley used in his work. This single item was the most important of all of his equipment. It created the spectra not from a  prism but a very special grating( made out of a relative common crystal) for analyzing the x-rays emitted from the elements of the periodic table that Moseley was studying. In this wavelength region prisms could not function, only gratings could work and in particular the ones nature made in the form of crystals, such as the crystal is shown below.  This natural grating should reside in  a brightly lit gilded glass case on a pedestal just as  with Galileo Galilei's famous Lens sometime does. They both gave all of us a better and very important view of the world we live in. Read on and see to see Mothers nature spectroscope designed and built a few years before Newton  set us all straight about rainbows. Bless him.
 


Doesn't look like much does it? Not going to win any academy awards will it? Galileo's Telescope and our replica of his telescope have stood out his museum for the public to understand and learn from.
 
Everything else around it was supporting equipment. There is some rumor that Moseley "borrowed" the crystal from the Bragg's experiments as well as their  theory generated for the crystal. another hint about scientists they physically and intellectually share their work.

 

On the other hand THE  PHOTO BELOW SHOWS  Henry Gwyn Jeffreys Moseley as a STUDENT WITH  STUFF IN HIS HANDS GRABBED OFF THE NEAR BY LAB TABLE READY AND WILLING TO BE THE NEXT  MEDIA HERO TO BE CELEBRATED GOOD GUYS IN THE  "Mystery of Matter".  Moseley had another hero thing going for him.  right after his discoveries He was kill by sniper fire in WW I. He than acted as sort of a poster scientist  recommending (by his absence )that scientists be relieved of active duty in time of war. There were lots of talented people lost in that war. Another famous grad student scientist Marie Curie saw the products of war, First Hand, by working  with her x-ray truck x-raying solder's battle wounds during WW 1. Below is photograph of the  Replica we made of from one of Moseley apparatus.

The modern  humans view of the world with Young Moseley's help. With others he took on the x-ray region.

 

The object of Moseley's method of research was to generate the spectra of each element to be measured with all its electrons stripped from that element. All but one. From natures point of view, that element then thought it was hydrogen  therefore it would give a hydrogen spectrum.  It did ...  but not exactly. The protons pushed the spectra  into the blue blue blue blue x-ray  region of the spectral world. The spectrum was pushed by the numbers of protons in the center of the atom.   This measurement technique could be done  experimentally from the spectrum generated by the magic crystal above. The crystal that knew it was a spectra generating grating and that       it  was not a prism at these short wavelengths. The bottom line not only did it verify Bohr atomic theory  of what an atom looked like it gave a better reckoning of the atoms in the periodic table. All this in doctoral theist. Madam Curie gained her Hero status in her doctoral theist also also with a lot of support from colleagues.


Back to the picture of  the humble nonchalant pose of Moseley grasping the bits and pieces of stuff he had swept off the bench  for this hasty shot.
Seems that everyone uses  this photo  to sell their web site whether the photo is relevant or not. Its a magnet. (
sorry about that.)

In particular note the circular pot  out in front. It  holds the All important measuring instrument , the x-ray diffraction crystal  spectrometer.   The glass apparatus behind it holds  the sample and the its x-ray exciting electron gun. A simple 1/8 " piece of wire with a 3/4 " diameter concave disk stuck on the ends of it to supple the electrons for the target .

One can note From the number of faces presented in the beginning Henry Gwyn Jeffreys Moseley a grad student is not the  sole Hero of these pages.  He was a very young man and had  been  encouraged by Lord Rutherford, Bohr,  consulted with the Bragg's (father and son),  about a project.

Some implied data  to this web site alerts those who want to get a more basic   understanding of how  the team work approach in experimental science really works.

 

Some of our work for this project  was to get a clearer first hand understanding of the Moseley experimental operation.
We show  in full color the equipment  that  we (Jim and Rhoda Morris) have built using NSF monies and donating much of our time replicating   Moseley experimental set up. We built a working instrument for a movie titled Mystery of Matter. We have done this for one to see a little more into our beloved science and how its team of individual competitive scientists work  really well together to get it right ... Quite incidentally ...  for your and our richer life.  Most don't appreciate this and don't have the inclination to care. It just happens.

We take on more step showing this team process. We  put forth ( with Moseley own words)  describing this  in his abstract, of the famous paper where he is reporting his results.

Take the time to see how Moseley  put his role  in perspective to the others scientist  who he was working closely with.

Below the abstract of Moseley Paper

giving the credits due and his approach to the research.

THE HIGH FREQUENCY SPECTRA OF THE ELEMENTS

By H. G. J. Moseley, M. A.
Phil. Mag. (1913), p. 1024

In the absence of any available method of spectrum analysis, the characteristic types of X radiation, which an atom emits if suitably exited, have hitherto been described in terms of their absorption in aluminium. The interference phenomena exhibited by X-rays when scatted by a crystal have now, however, made possible the accurate determination of the frequencies of the various types of radiation. This was shown by W. H. and W. L. Bragg, who by this method analyzed the line spectrum emitted by the platinum target of an X-ray tube. C. G. Darwin and the author extended this analysis and also examined the continuous spectrum, which in this case constitutes the greater part of the radiation. Recently Prof. Bragg has also determined the wave-lengths of the strongest lines in the spectra of nickel, tungsten, and rhodium. The electrical methods which have hitherto been employed are, however, only successful where a constant source of radiation is available. The present paper contains a description of a method of photographing these spectra, which makes the analysis of the X-rays as simple as an other branch of spectroscopy. The author intends first to make a general survey of the principal types of high-frequency radiation, and then to examine the spectra of a few elements in greater detail and with greater accuracy. The results already obtained show that such data have an important bearing on the question of the internal structure of the atom, and strongly support the views of Rutherford and of Bohr.

Kaye has shown that an element excited by a stream of sufficiently fast cathode rays emits its characteristic X radiation . He used as targets a number of substances mounted on a truck inside an exhausted tube. A magnetic device enabled each target to be brought in turn into the line of fire. The apparatus was modified to suit the present work. The cathode stream was concentrated on to a small area of the target, and a platinum plate furnished with a fine vertical slit placed immediately in front of the part bombarded. The tube was exhausted by a Gaede mercury pump, charcoal in liquid air being also sometimes used to remove water vapour. The X-rays, after passing through the slit marked S in Fig. I, emerged through an aluminium window 0.02 mm. thick. The rest of the radiation was shut off by a lead box which surrounded the tube. The rays fell on the cleavage face, C, of a crystal of potassium ferrocyanide which was mounted on the prism-table of a spectrometer. The surface of the crystal was vertical and contained the geometrical axis of the spectrometer.

In almost all cases the time of exposure was five minutes. Ilford X-ray plates were used and were developed with rodinal. l


Going  beyond  just our young  HERO ...  Moseley ...  and his atom project, one has the chance to  see here pictures and comments showing that  no scientist stands alone in any discovery.  No one scientist is a super being. Proper training, persistence, being at the right place, right time, are all any scientist can hope for.

All scientists are surround by  colleague's, who are both young and old painting  an emotionally stimulating, picture, of a spectrum of an internationally - diverse group of hard working  scientist.
Beyond many peoples belief that even though scientists  - are fiercely competitively, they work intensely together.  Specifically they are on one long term project which is hidden from direct view of the public but appears
( to some ) as taking a part of a - - never ending  paving  - of a road - to make everyone's journey into the future gentler and fuller.

This togetherness picture when ever painted appears  to be unbelievable by the general public.  They view scientist as  just another group of themselves  exhibiting  all the good and not so good ways of human nature. Few if any us have worked side by side  for or with a number senior performing scientist. Non of us will ever have or want to have to do this  for an extended length of time to  see what it is really all about.

Hmmmm just Hmmmm


Remember.
At the heart of young Moseley's instrument was a unique crystal  grating using  
Bragg's (fellow scientists) Law to make an x-ray grating spectrometer. Prism's do not work in x-rays region of the electromagnetic spectrum. Sorry Mr. Newton we can't use all that beautiful work you published. You should have been on Young's view of electromagnetic radiation.

Such an instrument was hovering around  near by in the Bragg clan  laboratory area. They were interested in measuring the arrangement of atoms in  crystals.

Bohr who was around on and off visiting the neighborhood
drawing pictures of models of his atom ands making calculations of his arrangements of the pieces in his model of the hydrogen atom using just the visible spectrum data taken from lots of other scientists.

 

The latest periodic  atomic  arrangement  of atoms in nature suggested from Moseley approach and data which he  obtained from one or more of  his grating spectroscopic measurements.


_______________________________________________________________________________

 The following are some scraps and unfinished business in this web site.

Below is a photo of a capillary hydrogen light source viewed through a transmission grating. Each side of the center pinkish red line which is the direct view of the hydrogen source are the alpha beta atomic lines in the visible spectra.

 

 The latest periodic  atomic  arrangement  of atoms in nature suggested from Moseley data which he  obtained from one or more of  his grating spectroscopic measurements.



The first Spectroscopic  Analysis deriving the concept of  Atomic Number.
 Also Moseley's experimental verification or Bohr approach in describing the structure of the atom.
This was a profound example in understanding how  scientist work.
Which is never alone but a serial step by step of competitive corporation with each other checking, cross checking each other, their models  which they pass on to the next group of  scientist.

 

Making Replication  of Moseley apparatus that he used for arranging - rearranging  the Periodic Table

Our contribution to this stew of science has been acting as contributors to the Moseley story  as part of NSF sponsored documentary  called  The Mystery Of Matter. We were asked to replicate his instrumentations. We had the pleasure of visiting Oxford University and take measurement of what was  left of his equipment. Having done this were in the position to replica his equipment and experiments more faithfully.

By Jim & Rhoda Morris

http://www.scitechantiques.com
 

From the book of Genesis 1.3,  God said  "let there be light"-- And God saw that the light was good".  A  scientist said "give me some electrons  I'll push them around and  they will give us light. Is this  good?
Moseley pushing electrons around and studying the light that they gave off with his light measuring scientific instrument **The spectroscope**saw that it is was good.  Good for his reputation. It wasn't it good for  those scientist's reputation's who had put  elements  in  the wrong box of the periodic table.

They had not  been using ** the spectroscope**  to get the right answer. Was it good for  science's  reputation showing that scientist  could be wrong?  Was it good  for the human race who gained  a better life with the "right; or almost right answer?"

Moseley used the same  optical style of spectroscope as  pictured above, but he  used a diffraction grating rather than a prism. Both the prism and the grating divide up the light into its colors but  Prisms do not work in the x-ray region. Some X-Rays- if they are strong enough - pass through a prism but without bending very much if at all into their colors.

Moseley gathered his experimental data  in  x-ray region of the spectrum  using single  crystals  to divide up the light into its colors.  Earlier than Mosley, Marie curie used x-rays to find bullets in soldiers bodies in the war I. The same kind of bullets that ultimately would kill Moseley who chose to fight in the war, which he used  to correct the mistakes others made  in the placement of elements in the  Periodic table. He even  predicted that scientist had been missing elements  in this table. 

Planetary atom: Far more  than the finding of empty holes in a table of elements, Rutherford likened this kind of research as stamp collecting.  Moseley had used his spectroscopic data to experimentally check, verify and select the interesting and then current theoretical model offered to explain the nature of hydrogen atomic spectra. The one he chose was the  classic Bohr's picture of a planetary atom. The theory in its simplest form fit hydrogen spectra which didn't last very long before it was modified  with a statistical approach. Still  it was a significant start.

Interesting planetary models were a hot topic in Galileo's time to some  and certainly to some historians looking for connections.  Galileo 300 plus years ago was struggling with another  . The model  of our solar system.  He was gathering acceptable data using a critical component of a spectroscope-- the telescope in his work. See the last picture  in a collage of  two  replicas of Galileo  telescope made into a spectroscope with prism. 

"Note" Simply replacing the prism with a rock salt grating one could use this spectroscope in Moseley experiment today.

Science was on a roll around 1900's +- 25 years  when Moseley' appeared on the  scientific scene.
In Moseley's time scientist had made enormous  improvements in  scientific instruments that expanded human's sense ,of  seeing, hearing, feeling, etc.,  millions of  times greater  than nature provided.  Example humans  in  Moseley time had to get acquainted with very tiny and very large things at the same time not only single atoms but parts of the atom, electrons, that they could not see directly. The Lorentz radius of the electron, 2.8 * 10 ^-13 cm.. The diameter of the nucleus of hydrogen  proton was in the range of  (1.7510−15 m)    On the larger size they have had to  start dealing with a universe billions of light years in radius. All this with the new scientific instruments with the little valued spectroscope leading the way.

Gaining perspective  of the instruments that Moseley's had available to work with were improvements in  vacuum technology (from the lighting world), high powered high voltage power supplies (from the power distribute system to light the world), new and more precise spectroscopes (from the analytical chemical world).  Added  to this arsenal was the statistical mathematics from the (business world).

The hottest scientific topics were the discoveries of particles that atoms were made of  electrons protons x-rays and especially  Marie curie's discovery of the enormous energy of the nucleus and Einstein's E=mc^2 were keeping the world of science flat out.


Moseley luck  and borrowed gifts from many others  was his fascinated with  high vacuum pumps , high voltage electron beams and the x-ray grating spectroscopes.

For the latter if we go back in time one of the simplest examples of humans relationship with  spectroscopes, were nature's  rainbows.   Humans could only view  the  sun's radiation using their natural senses. They noted that  exposure to sun meant  sunburns  - later  refer to as ultraviolet radiation, the visible perception  colors light like the rainbow, the sun's warmth  later called infrared radiation.

In our ,new,  world Moseley decided  with help from his adviser to use  a famous senior scientist, Dr.  Bohr, last gasping attempt to use classic mathematical methods to build  a formula to predict   the spectral light coming from  very hot  electron temperature) hydrogen plasma.  Moseley  using this incorrect (in the quantum mechanical  sense) theory decided to count the number of individual protons in atoms using man  made rainbow generators (grating spectroscope made using a large crystals  grown from table salt as the light dispersing element ). His goal was to correct the chemist's catalog of elements and the pieces  they are  made of, appearing (15,000 K)in the Period Table.

Again Quoting from Genesis
 In the beginning "and darkness was upon of the deep'" and "and God  said" let there be light"- In science the rainbow spectroscope was showing scientist the way to  go both big and little with the planetary model.

The cave mans view of his world.


 

Nature's spectroscope; using  spherical ( oblate spheroid to be more exact) rain drops Light from the sun passes thru rain drops forming a spectrum which we call a rainbow. Note in the photo hidden from the human eye are radiations beyond  the red and blue.

 -Unfortunately to some?-  humans  could only see a tiny portion of nature's infinite number of colors.
Figure 1 below shows how the visible spectrum connects with the rest of what scientists now call the electromagnetic spectrum. between the names radio frequencies, visible, and gamma rays.
The point here is to note that there is this  limitation in all  our  senses  ; light, hearing, touch, smell, etc. Some would even include common sense in the list?  -Fortunately?- scientist have extended all of our physical senses , perhaps with exception of one, with scientific instruments to expand our exploration of the world.
 

The Electromagnetic spectrum--
The figure below may seem complex to many people. The names do not seem connected. This is because as the scientist we're exploring each new radiation they needed a unique detector  they gave that portion of the electromagnet spectrum  a unique name.  In the final cut the only difference is in the size of the wavelength or the frequency of the radiation.

 

The modern  humans view of the world 


figure 1

Nature has  determined that all elements when heated to a high  enough temperature will  give off and or absorb radiation (each with a unique rainbow) they appear  in  very special places spread about the electromagnetic spectrum.  Scientist call these "rainbows"  "spectra. It helpful to many to think of spectra  as barcodes because  spectra look and act just like barcodes.  A special example for our purposes in replicating Moseley work on the periodic table we show the reader the spectra Moseley considered to be most important was the simplest element of them all  hydrogen. Again, Moseley  decided to make all element act with hydrogen  because hydrogen's spectra is simple and most important forecastable . One of the spectra that hydrogen gives off "light" is in the visible. It almost a poetic in shape as shown  below). It has a pair of lines red an blue followed by clump lines quickly gathering  together in the blue and deep blue to form almost a continuum. For our convenience we do not show the thousand and thousands lines  bunched up here in the deep blue. This spectra had  been labeled by a number of scientist around Balmer time  as the Balmer Series. It shows up in the visible.  Another set is similar is the  configuration the Paschen series appears in the infrared and a third  Lyman Series in the super Blue.

Top spectrum in the  figure below shows  the strongest visible lines of atomic hydrogen.
The spectrum below  is hydrogen like but in the x-ray region which is invisible to the human eye. Theselines are easily photograph however .
Note the strong similarity of the on top and bottom spectra. Actually their is one small change in the lines on the photographic plate. They have been  enlarged wavelength to show their similarity.  The reason the hydrogen like lines are in the x-ray region they are  not from hydrogen.  They are from heavier elements that have had all of their electron shot away with stronger electrons. This leaves the nucleus in tack but strongly positive. The first electron to come back to  the element gives a hydrogen like spectra but in an  x-ray region. By measuring the wavelength one has measured the  number of protons  in the nucleus which is the atomic number.is waiting to be places in the period table.


 

Summary
All elements can be electrically excited to produce a hydrogen like spectra
by
  simply stripping off all of its electrons. Moseley did this by shooting electrons generated from  a high voltage source at  a target of the atoms being studied. This generated  a source of  the ionized elements that would produce a  one electron type hydrogen spectra however they will be shifted toward shorter wavelengths in the x-ray spectra due to the higher number of protons in the element.  One can use this spectral shift to measure the element's atomic number, Z (its number of protons). Shown above is the spectrum for hydrogen and the corresponding hydrogen like spectra for the test element being measured in the x-ray region.

Moseley and fellow scientists devised equipment and experimental methods in spectroscopy to  include the x-ray wavelength region of the spectrum, the region necessary for measuring the number of positive charges in the nucleus of atoms. By accurately measuring this unique number (known as the atomic number, Z) for each element they were able to accurately determine the location of an element in the periodic table and even predict empty slots and what the element  might act like . This table is  one of the most important catalogs or spreadsheets for science and engineering.

Moseley's work was far more reaching than the periodic table. His work helped give experimental verification of models explaining what an atom might physically look like, namely Bohr's planetary model of the atom. Below one of a number Moseley's later instrument used to measure the atomic number of the  elements.

Below is one  of a number of experimental set ups used to in Moseley's
  studies.

 

Below is a our  replica of the glass and metal components shown in the picture above.

By producing hydrogen like spectra from totally ionized atoms of a relatively large number of elements in the x-ray region Moseley found a method to accurately position the  elements in our periodic table.

 

 

To the left is Moseley and some of his apparatus.  To the right in the figure above is Moseley's hydrogen like spectra  showing the alpha and beta spectral lines for  variety of elements including Copper, Nickel, Cobalt, Iron, Manganese, Chromium, Vanadium, Titanium, missing element, Calcium.


Below: We generated the atomic spectrum of hydrogen from a low pressure gas discharge tube for readers satisfaction at the simple yet complex spectral features Moseley had to deal with in his experiment. We show what happens when one looks through a grating spectroscope at hydrogen heated by electrons in what scientist call in this instance a gas discharge tube, a very important accessory in science.  Moseley used a source of electron also but bombarded solid  targets to  strip all the bound electron of the atoms. As the electrons rejoined the atom the first ones generated  a line spectra similar to a hydrogen spectra but in x-ray region located by the number of protons in the atom.

 In the figures below---Looking through a transmission diffraction grating at the discharge tube, one will see in the center, the primary non refracted image of the discharge tube. On each side of this center image are the images of the diffracted first and second orders of the hydrogen alpha and beta spectral lines. There are more spectral lines (see figure above) too faint to be recorded by the camera. This was the true of Moseley's  x-ray spectrograms. This spectrum shows the skill Moseley needed to separate  the parts of the spectrum need for the measurement.


 

Spectra of atomic hydrogen as viewed through a diffraction grating

 


 

The hydrogen low pressure arc source.



The diffraction grating in the foreground the arc source in the background

 

The light source as seen looking through the grating

----------------------------------------------------------------

The collage  in the photo shown below  shows one of the greatest irony of science. Galileo  had in his hands all of the basic components to build a spectroscope of one of the most important scientific instruments invented. It took nearly 300 years  and a frog to bring the rest of the equipment  needed  up to speed to  see  "a atomic planetary " system..   Planetary, a concept, a word, challenged by a Catholic church only to  be  replicated in atomic dimensions.  Protons circled by  electrons.  In this case the planets (electrons ) are giving off the light. not the protons (the sun).

 

 -----Rhoda and Jim comments----Oh how slow some instruments take to be developed. Two very precise replicas of Galileo Telescopes turned into one of the  most powerful scientific instruments of all times. It took nearly 359 years to add a simple prism and input slit to  discover the tremendous value such a simple instrument. The most important missing link was the battery which allowed us to heat up atoms and molecules hot enough to generate their spectra. We also needed a good vacuum system to achieve low pressures for exciting even higher temperature to see ionic spectra. The spectroscope has given us quantum mechanics, shown us the size and content of the universe etc..

 

 

 

 Below the abstract of Moseley Paper

giving the credits due and his approach to the research.


THE HIGH FREQUENCY SPECTRA OF THE ELEMENTS

By H. G. J. Moseley, M. A.
Phil. Mag. (1913), p. 1024

In the absence of any available method of spectrum analysis, the characteristic types of X radiation, which an atom emits if suitably exited, have hitherto been described in terms of their absorption in aluminium. The interference phenomena exhibited by X-rays when scatted by a crystal have now, however, made possible the accurate determination of the frequencies of the various types of radiation. This was shown by W. H. and W. L. Bragg, who by this method analyzed the line spectrum emitted by the platinum target of an X-ray tube. C. G. Darwin and the author extended this analysis and also examined the continuous spectrum, which in this case constitutes the greater part of the radiation. Recently Prof. Bragg has also determined the wave-lengths of the strongest lines in the spectra of nickel, tungsten, and rhodium. The electrical methods which have hitherto been employed are, however, only successful where a constant source of radiation is available. The present paper contains a description of a method of photographing these spectra, which makes the analysis of the X-rays as simple as an other branch of spectroscopy. The author intends first to make a general survey of the principal types of high-frequency radiation, and then to examine the spectra of a few elements in greater detail and with greater accuracy. The results already obtained show that such data have an important bearing on the question of the internal structure of the atom, and strongly support the views of Rutherford and of Bohr.

Kaye has shown that an element excited by a stream of sufficiently fast cathode rays emits its characteristic X radiation . He used as targets a number of substances mounted on a truck inside an exhausted tube. A magnetic device enabled each target to be brought in turn into the line of fire. The apparatus was modified to suit the present work. The cathode stream was concentrated on to a small area of the target, and a platinum plate furnished with a fine vertical slit placed immediately in front of the part bombarded. The tube was exhausted by a Gaede mercury pump, charcoal in liquid air being also sometimes used to remove water vapour. The X-rays, after passing through the slit marked S in Fig. I, emerged through an aluminium window 0.02 mm. thick. The rest of the radiation was shut off by a lead box which surrounded the tube. The rays fell on the cleavage face, C, of a crystal of potassium ferrocyanide which was mounted on the prism-table of a spectrometer. The surface of the crystal was vertical and contained the geometrical axis of the spectrometer.

In almost all cases the time of exposure was five minutes. Ilford X-ray plates were used and were developed with rodinal. l