Publisher's Statement

Since its beginnings in 1886 until its untimely demise in 2002, Arthur D. Little, Inc. (ADL) was considered the premier research, development and engineering consulting firm in the world. Literally, hundreds of products and inventions for companies and Government entities arose out of its laboratories.

This blog is an attempt to tell the stories behind these products and inventions, told by the ADL staff members who were involved in the development, or have a close knowledge of the details.

My name is Irving Arons and I was a member of the staff of the Product Technology Section of ADL from March 1969 until my retirement from the firm in March 1994. During my tenure at the company, more than half of my career was spent either working on developing products in the laboratory or leading laboratory-based projects that were sponsored by companies and Government entities such as NASA. (The latter half of my career was spent as a specialist in ophthalmics and medical lasers as the leader of the Ophthalmic and Medical Laser Consulting Group, preparing research reports for companies in those fields. These reports and other published writings in these fields can be found in my other blog, Irv Arons’ Journal on the web.)

I have prepared and posted several writeups on laboratory projects I was involved with and invite my ADL alumni colleagues to share their product and invention stories on these pages. If you have any questions on any of the posted materials, please contact me, using the email link Irv Arons. I will do my best to amswer your queries as quickly as possible.

Of Silk Purses and Lead Balloons

Contributed by Irving J. Arons, Product Technology 1969-1994.

The purpose of this posting is to tell the true story of how, in the early part of the 20th Century, dedicated chemists and engineers at Arthur D. Little were put to the task of breaking the adage that you couldn’t make a silk purse from a sows’ ear. And then, some 50 years later, in 1977, how another group of dedicated scientists at the company decided to do it again, and this time show that lead balloons really could fly.

The Silk Purse (1)

In 1921, in order to obtain some favorable publicity for his fledgling company, Arthur Dehon Little, the founder of Arthur D. Little, Inc., of Cambridge, Mass., decided to challenge his chemists and engineers to create "silk" from pork byproducts. The idea behind this surprising and not very practical experiment was to prove that something said to be impossible was, with sufficient effort and ingenuity, attainable. The old adage that said, "you can't make a silk purse of a sow's ear" had been used for years to discourage inventiveness and enterprise. As Arthur himself stated, "We resolved...to prove that it was false, and we have done so. We have made a silk purse of a sow's ear."

The chemists' first step was to observe the production of silk by silkworms, analyzing both the process and the product. They found that the viscous liquid emitted from ducts in the worm's head turned to silk after contact with air and that it was chemically akin to glue. Following this lead, the lab purchased one hundred pounds of sows' ears (certified to be authentic by an affidavit from the supplier, Wilson & Company, meatpackers in Chicago) and reduced it to ten pounds of glue, which was turned to gelatin by adding small amounts of chrome alum and acetone. After much trial and error the chemists hit upon a means of producing fine strands by filtering the gelatin under pressure and forcing the substance through a perforated spinneret. The resulting brittle strands, softened by bathing in a glycerin solution, were dried, dyed, and woven into cloth of "the desired soft, silky feel." From this cloth two ten-inch long "silk" purses were cut and stitched in imitation of a medieval design, used for holding silver coins in one end, and gold in the other.

The company freely acknowledged that the two "silk" purses, expensive to produce, had more value as conversation starters than as items intended for practical use. They were widely exhibited at trade shows and promotional events. "We frankly admit," the company stated, "that it is not very strong or very good silk, and that there is no present industrial value in making it from glue."

A report about the project (2) concluded: “Things that everybody thinks he knows only because he has learned the words that say it, are poisons to progress. The only way to get ahead is to dig in, to study, to find out, to reason out theories, to test them...

This making of silk purses of sows' ears was merely a diversion of chemistry at play. When chemistry puts on overalls and gets down to business, things begin to happen that are of importance to industry and to commerce. New values appear. New and better paths are opened to reach the goals desired.”


One of the purses was presented to the Smithsonian's National Museum of American History. The other was proudly displayed in the Boardroom of the company, at 25 Acorn Park until the company declared bankruptcy in 2002, at which time it was put up for auction.

The silk purse was obtained by Kenan Sahin, the founder of TIAX, the successor company to the old Product Technology Section of ADL, and is now part of that company’s ADL memorabilia display.

1. On the Making of Silk Purses from Sow's Ears: A Contribution to Philosophy, Arthur D. Little, Inc, 1921.

2. "On the Making of Silk Purses from Sows' Ears," 1921, MIT Institute Archives & Special Collections.

The Lead Balloons

In March 1977, Jim Birkett, a senior staff member of Arthur D. Little, came up with the idea of the company sponsoring a contest to see if any of its staff could come up with a way to break another adage – that lead balloons couldn’t fly. This was the beginning of The Great Lead Balloon Contest.

Jim formed a blue-ribbon committee of senior management (and the daughter of Public Relations Director Alma Triner, Kim Triner – a noted Juvenile Balloon Addict) and issued a Request for Proposal (RFP), which spelled out the specifications for flying a lead balloon. Proposals were due on March 30th. In all, six teams responded with proposals of how they would solve the problem and build and fly a lead balloon. The Blue Ribbon Committee selected three approaches, announced that they would supply 0.8 mil lead foil (tissue-paper thin) and helium, and that the “fly-off” would be scheduled for Friday, May 13th.

One team, headed by Marie Chung, Warren Lyman, and Ed Dohnert, proposed to build an 8 foot diameter by 14 foot long endoskeletal balloon/dirigible, built on a balsa wood frame. It was dubbed the “Lead Zeppelin”.

A second team, headed by Jack Ennis and Sid Meyers decided on a traditional spherical, non-rigid design. They would build a scrim-reinforced lead foil outer skin, backed up by a conventional 10 foot diameter weather balloon. Their intent was to fill the space between the reinforced foil and the weather balloon with helium, allowing the air in the weather balloon to escape and eventually remove the balloon. That proved difficult or impossible to do, and the helium was eventually contained within the weather balloon – not the foil.

My team, headed by Ken Sidman, Paul Monaghan and Art Schwope, went with a cubist/Origami design, suggested by Paul Monaghan, that was basically a nine-foot cube to be folded flat and unfolded or opened only during inflation to ensure that there would be no air trapped inside, thus the “Origami” moniker. The lead foil strips were to be held together using one-sided adhesive tape, and the side seams were to be reinforced with adhesively-held scrim.

As previously mentioned, the “fly-off” was scheduled for Friday the 13th of May. But, due to excess wind conditions, the lift-off was postponed to the following Monday, May 16th.

The event was covered by the press – AP and several local newspapers, as well as by a local Boston TV station.

As the event unfolded, our cubic balloon began inflating and unfortunately, due to a technical problem, one of the side seams stuck to the bottom panel and tore a huge hole in the bottom of the balloon as it inflated. In a post mortem, we concluded that we should have put some talc over the adhesive bonded scrim to prevent it from “blocking”.

But, in fact, our cubic balloon creation did lift some 12 feet high off of the ground (see first set of photos). I know this because I was underneath the balloon, trying to place the “silk purse” in a gondola-like basket for the historic ride! A gust of wind came along, whooshing the helium out of the gaping hole and the balloon collapsed on top of me.





The spherical balloon lifted off of its launching pad, broke its tether and landed about a mile down the road off of our ADL complex.

But, the third balloon, the Lead Zeppelin (photo below) took the prize. It too broke its tether and was last seen heading toward Logan airport – about six miles from ADL. Someone on the balloon committee realized that it would show up on Logan’s radar and called the control tower to warn them about our problem. After some laughter on the part of the tower personnel, they began tracking our IFO (Identified Flying Object) and it was last spotted by a commercial aircraft out over the Atlantic Ocean headed toward Europe!


After the contest Art Schwope noted, “By definition, a balloon is an inflatable structure. The so-called winner of the contest was a design based on the lead foil being placed on a rigid, wooden frame. It was filled with helium but not inflated by helium. It was a zeppelin, not a balloon.”

The spherical balloon really wasn’t one, either. It was “built as an over layer of the lead film on top of a weather balloon. The intention was to remove the weather balloon for the contest, but that proved difficult or impossible. Thus the helium was contained by the weather balloon, not the lead foil.”

In short, there was only one, true lead balloon.(Ours.) It didn't fly high or far. But it was the only inflatable structure in which the lead film contained the helium. Yes, technically it was a failure, but true to the nature of ADLers, we considered it a success, as it was the only lead balloon and it did fly (for a short time)!

So, once again, the scientists at Arthur D. Little had done the impossible and shown that lead balloons could be made to fly.

The EPCON Plastic Pencil

Contributed by Irving J. Arons, Product Technology 1969-1994.

In 1969, Hasbro Toy Company hired the Product Development Section (as it was known at the time) of Arthur D. Little, to develop an all-plastic pencil. Wood pencils were made of red cedar grown in the Pacific North West, while Hasbro’s pencil subsidiary, Empire Pencil Company, operated out of Shellbyville, Tennessee, in the South East.

Wood pencils are traditionally made by grooving half slabs of red cedar; placing ceramic graphite leads into the grooves and gluing the two slabs together. Individual pencils are then hand machined from the glued slabs, painted, eraser ferrules attached, and then packaged for marketing. The idea behind the all-plastic pencil was to reduce product costs by eliminating the hand machining and providing an automated production process.

The ADL effort was led by Richard Merrill. I worked on the composition of the materials for the pencil casing, which had to be as stiff and sharpenable as its wooden brethren, and Richard Merrill, Bob Eller, and Arthur Drennan worked on developing a co-extrusion process wherein a “plastic lead” could be extruded within the plastic casing to make a continuous plastic pencil.

After making and testing hundreds of casing composition formulas, I settled on a mixture of ABS plastic, wood flour (for sharpenability), and aluminum stearate (for lubrication during the extrusion process). (The “plastic lead” was supplied by Empire Pencil.) While the casing compound was under development, several iterations of the co-extrusion processes were tried, until a co-extrusion mold and process was found that could be successfully used to produce the plastic pencils.

About 5 years after the project initiation, in 1974, a casing formulation and co-extrusion process were finalized, and the plastic pencil was born (and patented (1-3)).

A pilot line was set up in Empire’s plant in Shelbyville and. after some fine-tuning, pilot production was set. Soon after, several additional extrusion lines were established, and by 1975, the EPCON pencil began commercial production.

The pencils were produced “by the mile”, painted in-line, cut to length, an eraser and ferrule attached, and packaged for sale.







1. U.S. Patent No. 3,875,088, Pencil Sheath Compositions, Irving J. Arons, Robert Eller, Richard E. Merrill, April 1, 1975.

2. U.S. Patent No. 3,983,195, Pencil sheath compositions, method for making pencils, Irving J. Arons, Robert Eller, Richard E. Merrill, September 28, 1976.

3. U. S. Patent No. 3,993,408, Pencil comprising a marking core and a porous resin sheath, Irving J. Arons, Robert Eller, Richard E. Merrill, November 23, 1976.

Also see: Wikipedia.org -- Pencil.

Spin-cast Eyeglass Frames

Contributed by Irving J. Arons, Product Technology 1969-1994.

In the summer of 1976, Universal Optical, an eyeglass frame manufacturer called and asked ADL to see if it could develop a process for manufacturing an epoxy eyeglass frame, similar in properties to that of Optyl of Germany.

Optyl had developed and was marketing a high-style frame that could be shaped to fit the wearers face but that would hold that shape, unlike normal plastic frames that quickly loosened on the face. Plastic frames, until that time, were typically made of cellulose acetate and the “ears” required a metal insert to maintain their shapes over the ears.

I led the case for ADL’s Product Development Section, ably assisted by my boss Richard Merrill, Arthur Drennan, and Karen Lanzon (Evans). The first thing we did was to develop an epoxy-based material that had the right properties – low viscosity, quickly cured, and that had the proper hardened properties required for an eyeglass frame, i.e., rigid, strong, clear (so that it could be dyed to any color), and malleable when heated for adjustment. After producing and testing several formulations, we found the right formula and went on to the next problem.

Our biggest problem was developing a method for making finished frame parts. We settled upon a method used in the jewelry and small pewter figurine businesses, spin casting. After much trial and error, we were finally able to develop a process that produced both the ear pieces and frames – after overcoming a major problem of removing small air bubbles trapped in the parts that threatened to ruin our attempts. Arthur Drennan came up with a brilliant idea for venting our molds –using soda straws -- to overcome this problem.

Next we developed a dyeing process for coloring the frames according to the style of the day, gradient colors, and finally, found the right urethane coating to produce a lustrous finish.

After about three years of experimentation and development, the process was transferred to the client company’s plant in Providence, RI and a pilot program initiated. Unfortunately, Universal Optical was beset with other problems by this time, and the epoxy frame production was never commercialized. We were, however, able to obtain a patent (1) on the process that was assigned to the company.



1. U.S. Patent No. 4,294,792, Molded Plastic Parts, Particularly Spin-Cast Plastic Parts for Eyeglass Frames, Irving J. Arons, Richard E. Merrill, Arthur P. Drennan, October 13, 1981.

The Disposable "Motionless Mixer"

Contributed by Irving J. Arons, Product Technology 1969-1994.

In the early 1970's, MPB Corporation asked Arthur D. Little's Product Development Section to develop a "package" for two-part reactive adhesives that would not require mixing by the end user. I was the case leader for this effort.

After considering several different packaging techniques, including a two-part aerosol delivery system, the development team decided to use a disposable version of the Kenics Motionless Mixer, developed and patented earlier by an ADL team and licensed to the Kenics Corporation. The Kenics Motionless Mixer was composed of a series of eight bow-tie like stainless steel elements, bonded end to end and at angles to each other, within a stainless steel tube. The idea was to break up and disperse materials that flowed through the tube. It was used in the food and civil engineering industries for mixing air into water in ponds and lakes and for blending disparate food materials. The only problem was that the smallest of the Kenics mixers cost $100 each, well beyond what a throw-away product for mixing adhesives could bear.

The Stainless Steel Kenics Mixers

Arthur Drennan, one of the team members, was able to find a plastics molder capable of injection molding a unit of 8 bow-tie elements in the correct configuration, that could then be placed inside a hollow plastic tube which, when connected to a dual-chamber syringe, would perform the required mixing for two-part adhesives. The resultant mixing element was produced for pennies each and successfully fulfilled the requirements of the client.

Injection molded plastic bow-tie elements

Today, versions of this disposable mixer can be found in many hardware stores, packaged with two-part epoxy and acrylic adhesives, and is also found in virtually every dentist's office, used to mix the reactive components placed into the mouth to produce molds for dental bridges and caps and for cements to hold braces in place. Unfortunately, we were unable to patent this development.

Prototype assembled dispensers

The picture below shows how the Kenics mixer works, showing the mixing of a red and blue colored viscous material to create a "mixed" green composition:

An Improved Firefighter's Glove

Contributed by Irving J. Arons, Product Technology 1969-1994.

It all started with NIOSH (the National Institute for Occupational Safety and Health) in 1974. This Government Agency hired Arthur D. Little to determine what the dangers were that firefighter’s hands faced when fighting fires. The case was led by Gerry Coletta for ADL, and we studied Government reports and interviewed firefighters around the country, to come up with a potential list of hazards and how often firefighters hands were hurt, including the types of injuries.

We discovered that firefighters were usually supplied with coats and hats but were given an allowance for gloves that led them to purchase inexpensive gloves at the local hardware stores, which provided little to no real protection.

In a second assignment for NIOSH, we developed criteria and test methods to evaluate the protection provided by their clothing, including the typical canvas gloves they used. As part of this assignment, I developed a series of test methods to simulate the dangers that firefighter’s hands faced, including providing protection from cuts (from sharp edges such as metal and glass), punctures (from nails), conduction of electricity, conductive heat (from touching hot surfaces), radiant heat (from the fire energy nearby), heat penetration, and from flames themselves. In addition, I designed a test to provide for the flexibility needed for the firefighters to do their job. We tested the types of gloves firefighter usually wore against the criteria developed for these tests, and found the gloves used sorely lacking.

This led to an assignment, in 1977, from NASA (the space agency). They asked us to follow up the good work we had done for NIOSH and using the test methods we had developed, come up with an improved firefighter’s glove using “space age” materials. This case team was led by Richard Tschirch and Ken Sidman. We evaluated a number of newly available materials, originally developed for NASA’s use, to see if any could be adapted for use in firefighters gloves.

After much testing of many new-age materials, we settled on a neoprene-coated Kevlar fabric, backed up by Kevlar felt. This combination provided adequate protection from all of the test categories listed above. Two patents, covering our inventions, were issued (1, 2) and assigned to the U.S. Government, as represented by NASA.

Following publication of our work by NASA, several glove manufacturers took up the challenge and started producing the improved gloves, which were quickly adapted by firefighters around the world.


1. U.S. Patent No. 4,433,439, Heat resistant protective hand covering
Richard P. Tschirch, Kenneth R. Sidman, and Irving J. Arons, February 28, 1984.

2. U.S. Patent No. 4,454,611, Heat resistant protective hand covering, Richard P. Tschirch, Kenneth R. Sidman, and Irving J. Arons, June 19, 1984.

An Erasable Ink Composition

Contributed by Irving J. Arons, Product Technology 1969-1994.

In 1980, following the introduction of an erasable ink ballpoint pen by the Papermate Division of the Gillette Company in 1979, BIC Corporation approached Arthur D. Little to see if we could come up with an erasable pen ink that got around Gillette’s issued patents. Dick Brenneman headed up the case for ADL, and I was a member of the team.

What makes erasable ballpoint pens so different from traditional ballpoint pens is the "ink" -- instead of being made from oils and dyes, it is made of a liquid rubber cement. As you write, the ballpoint rolls on the paper and dispenses the rubber cement ink (the resulting mark is known as a trace). Modern erasable pens work by allowing a ballpoint pen to leave a definite and intense black or colored trace which looks like an ink trace, but is capable of being easily erased shortly after writing (usually up to 10 hours). After that time, the trace will harden and become non-erasable.

Erasable ink generally consists of 15 percent to 45 percent (by weight) natural rubber that is dissolved in a series of volatile organic solvents with varying boiling points.

We held several “idea-generation” sessions and, after much laboratory experimentation, finally found a formula that both worked as a ballpoint pen ink, and got around the Gillette patents. As noted in our issued patent (1), we found that the combination of a block thermoplastic elastomer and an appropriate plasticiser, with a slow evaporating solvent, achieved the goal of laying a mark (trace) on top of the paper that was erasable for a period of time until the solvent vehicle evaporated causing the ink to sink into the substrate (paper) and become permanent.

Thus, the BIC erasable ballpoint pen was born.


1. U.S. Patent No. 4,721,739, Erasable ink compositions, Brenneman; Richard S. (Natick, MA); Drennan; Paul M. (W. Newton, MA); Arons; Irving J. (Peabody, MA); Pincus; Alice H. (Andover, MA); Ramzan; Chaudhary M., January 26, 1988.