Translated by Ilse Roberts and Peter Abrahams
Text of this translation copyright 1996

Schomerus, The History of the Zeiss Works in Jena, 
Pages 241-3, The Zeiss Field Glass
The field glass was substantially improved in its first twenty five 
years, in several ways including optical improvements.  The year 1920 
brought the "wide-angle fieldglass" with the newly invented oculars whose 
70 degree field of view was half again as wide as earlier oculars.  In 
1937, f.o.v. was increased to 90 degrees.  In 1936 the T-optic [lens 
coating] was introduced, which eliminated light loss by reflection at the 
glass surface and raised the brightness by nearly half.  These brighter 
night glasses were especially useful to sailors, hunters and alpinists.

(*As can be learned from an article by Smakula in the Z.W.Z. (Zeiss 
Magazine) of June 1941, "What are Zeiss T Optics": During the passage of 
light through the glass, at the border between glass and air, part of the 
light (about 4-6% per surface) is reflected (thrown back).  The reflected 
light is lost; this is termed reflection loss.  The more glass surfaces 
there are in the instrument, the more light is lost.  For a prism 
fieldglass with ten border surfaces the loss is greater than 40 %.  The 
light intensity is diminished by that much, and the image produced by the 
optical system appears darker than it would be without the reflection.  To 
eliminate the disturbing reflection had for a long time been the desire of 
the optical industry, but without any expectation of practical 
realization.  As late as 1932, Professor M. von Rohr said that nothing 
could be done about it, since the reflection is inextricably connected 
with the refraction.  But in 1935 Zeiss succeeded in perfecting a 
procedure whereby the reflection of white light is greatly diminished, and 
at one-color of light is practically eliminated.  These optics received 
the name T-optic and were produced at Zeiss since 1935 for expensive 
instruments.  In addition to the large increase in light, a contrast 
increase is achieved which is very favorable for microscope objectives and 
especially for complicated instruments with a great number of optical 
parts.  See also: Smakula, About the increase of light intensity of 
optical instruments, Magazine for Instrument Science 60, pages 33-36 
(1940).  Dr. Albert Koenig initiated these concepts.  Dr. Alexander 
Smakula (born 1900 in Dobrowdy, Austria, employed October 1 1934,) has 
succeeded in the development of the procedure.)

Significant reductions in the weight of binoculars were another 
achievement.  This was important to the person carrying the fieldglass, as 
an old brass model that weighed 670 grams, was only 330 grams with the 
Elektron metal housing of 1933.  This metal is an alloy of aluminum, 
magnesium, and silicium, with corrosion resistance increased by a galvanic 
procedure (Eloxal).  The lightweight field glasses and theater glasses 
were made handier in 1926 with the introduction of the flat models with 
roof prisms.

The Zeiss glass remains, in spite of many imitations, one of the most 
popular and widely sold binoculars.  Because it was so popular, after the 
first world war, racketeers and profiteers quickly took advantage of this 
and marketed forged field glasses, often with the name, trademark, and 
other markings of Carl Zeiss.  The main factory for this forgery was in 
Berlin.  Old military stock was bought and freshened up, worn company 
names and trademarks were renewed, model identifications were replaced by 
newer ones, and old and new glasses of other makers were engraved with the 
Zeiss logo.  At a police raid, hundreds of forgeries were discovered 
hidden in secret closets.  The energetic actions of Zeiss to uncover these 
outrages led to several criminal proceedings, with just one trial 
containing 13 defendants.  Forgers, fences, and black marketeers had to 
pay for their deeds with prison sentences and fines to Zeiss.  In foreign 
countries, for example in the French ports, these forgeries were executed. 
and they were finally suppressed by the enlightenment of the public and by 
criminal prosecution.

But the value of the Zeiss field glass can also be demonstrated by more 
positive documentation.  In numerous letters from famous scientist-
explorers and seafarers, its resistance against atmospheric influences in 
the desert, the tropics, on the oceans and in airplanes, was praised.  
Characteristic is the following:  On the reservoir of the Saale dam a boat 
went down in the spring of 1938.  A camera and a Zeiss field glass were 
lost to the passengers.  At a depth of 15 meters, the field glass 
slumbered in the mud since that time, and was considered to be a total 
loss.  When the water level was lowered 5 1/2 years later, the field glass 
reappeared.  With little effort and hardly any cost it could be restored 
to a state that was hardly distinguishable from a new one, and afterward 
served useful purposes.


Page 177, Zeiss and Bausch & Lomb
Another business connection with a foreign country was accompanied by 
many hopes, but was dissolved during the first World War.  The very 
important market of the United States of America had already closed itself 
off to imported optical products by exaggerated, high customs tariffs of 
25 to 49% of the product value.  To erect a factory in that country seemed 
injudicious and daring; and consequently in 1908 management decided, with 
the approval of the foundation, to enter an alliance with the important 
optical firm of Bausch & Lomb in Rochester, with whom there was already a 
connection through licensing contracts.  The firm of Saegmueller entered 
the alliance, as well.  Zeiss secured its influence with strong financial 
participation.  Also, the sale of Zeiss products in America was to be 
increased.  This connection was fruitful, and the invested capital brought 
good interest.  Visits by Professor Straubel and Dr. Bauersfeld to 
Rochester supplied information about American production methods which 
could be used in Jena, but also showed many weaknesses , which were still 
at that time part of American business practices.  In the World War, even 
before the entrance of the United States, Bausch & Lomb could not resist 
the temptation to deliver strategic instruments to England, which caused 
Zeiss to dissolve the connection.  There were no losses, since the sum of 
$817,260 was reimbursed on November 1, 1915.


Pages 86-92, Terrestrial Telescopes, and Especially Prism Telescopes
In the summer of 1893 the rumor went from mouth to mouth in the 
workshop, that professor Abbe, during his spring vacation in Switzerland, 
had invented a new kind of telescope and that trials were already being 
done.  Indeed, it was an idea that Abbe already had and pursued in 1873 
but discontinued.  The workers at Zeiss had enough to do with the 
requirements demanded by the microsope.  The opticians to whom Abbe showed 
his invention at the trade exhibition in Vienna in 1873 did not show any 
interest in it, nor did Carl Zeiss.  The Dutch or Galilean telescope was 
considered sufficient, although it only permitted small magnifications 
unless major defects in the image were allowed.  They were used as 
Krimstecher (named after the Crimean War where they were used) with three 
or at most five times magnification, and as opera glasses with 1 1/2 to 
three times magnification.  The time was not ripe for fundamental changes, 
proven by the fact that a solution from 1853 which approached Abbe's, by 
the Italian engineer Porro, (born November 25, 1801, died October 8, 1875) 
remained without success and was forgotten.  (*"Porro, an inventor of 
genius, especially in the geodetic area, died in poor circumstancess and 
depressed mood.  That his rich inventive gift was not successful may have 
been caused by the fact that he was not knowlegeable in optical 
calculations and didn't know how to perfect production procedures; also, 
his desire for improvements prevented economical fabrication." - Albert 
Koenig)  It probably was mainly the lack of a sufficiently transparent 
glass which precluded an early success, in addition to other technical 
difficulties.  Another factor may have been that just like the Galilean 
telescopes, the few Porro prism glasses which came to market were produced 
for monocular use.  However, the many varieties of Schott glasses now 
available, which could be adjusted to the different optical requirements 
of Abbe, allowed these prism glasses, along with new types of microscope 
and photographic objectives.  The prism telescope was created with the 
especially bright and clear borosilicate crown glass by Schott.

The events included some excitement and tension.  On July 8, 1893, the 
firm applied for a patent on the "image reversing prism combination" at 
the Imperial Patent Office.  They asked for patent protection for the 
combination of four reflecting prisms in a certain arrangement; and the 
usage of this image reversing prism combination for the production of 
single telescopes, and double telecopes where the objective distance was 
larger than the distance of the oculars and eyes.  A prism binocular built 
in such a manner has, like astronomical telescopes, a large doublet lens 
(two lenses cemented together) as an objective for the entry of light, and 
a set of three partly cemented ocular lenses for each eye.  The system has 
a long ray passage and at first produces reversed images.  Therefore, two 
more prisms are set into the ray passage, which erect the image by several 
reflections of the ray, and fold the long ray passage so that a short 
handy instrument is the result.

While the request was examined at the patent office, trials were done in 
Jena.  "If they are promising, we can congratulate ourselves and 
confidently begin a new production.", said in a letter of May 16, 1893 to 
the Foundation Commissioner Councillor Rothe in Weimar.  Abbe wrote to him 
in the middle of September 1893: "The experimental production in regards 
to 'handheld telescopes' is advancing well.  We now have firm ground under 
our feet for further advancement and for the judgement about the 
anticipated success and are, I hope, very close with the models, to a 
decision on the final forms to execute.  In a few weeks we shall probably 
be able to start factory production in full force.  We are no longer 
worried about lack of work for the winter and the forseeable future."  
(*This and the following letters of Abbe to Rothe are to be found in the 
papers of Councillor Rothe in his capacity as foundation commissioner of 
the Carl Zeiss Foundation and were graciously made available to me by the 
Thueringer States archive at Weimar)

Into this hopeful mood exploded the patent office report of November 17, 
1893: "The image reversal by four times reflection and the therewith 
connected shortening of the tubes, is already known, compare Eisenlohr's 
Textbook of Physics, 11th edition, edited by Zech, Stuttgart, published by 
J. Engelhorn, 1876, page 317, fig. 3 and fig. 359.  Such a Porro telescope 
which can be held by one hand and at the same time be adjusted, is for 
example owned by the Physical Institute of the Technical University of 
Stuttgart. . . . You may want to submit, within a month, new plans which 
are only concerned with the newness."  This knowledge of the patent office 
was due to the circumstance that one of its members remembered seeing such 
a prism combination when he was an assistant at the Technical Institute in 
Stuttgart, which the Italian engineer Porro had given to a physicist 
there, a friend of his.

How Abbe reacted to the patent office report, can be seen in two 
paragraphs in letters to Councillor Rothe.  On November 27, 1893: "For 
some days now we are terribly busy in regards to the patent application 
for an 'image reversing prism combination’.  The patent office has rooted 
out an old publication, apparently quite by chance, but not too late for 
our concerns, from the years 1853 and 1857 (coming from an Italian well 
known as a geodetic engineer), which give a complete description of the 
prism combinations in both sequences and at the same time several of the 
applications which we have pursued.  Our patent application therefore has 
to be quite limited. . . .The thing is of course very infuriating.  But we 
must console ourselves with the fact that, if we had known everything in 
advance, we would have proceeded in essentially the same way.  Czapski and 
I must now study the literature which the patent office indicated so that 
we gain assurance about what is still capable of being patented, and 
accordingly write a completely new patent application."  (*Of course one 
must not see a reproach against the patent office in this expression of 
Abbe's.  The office had to make known what it knew, according to paragraph 
2 of the old patent law)  On November 30, 1893: "In regards to the 
telescope affair, we are not at all sorry about the disappointed hopes.  
These delusions have the advantage that they do not impoverish the deluded 
more than he would be without the delusion, but more often make him 
richer.  And we find that the latter is true for us: we would hardly have 
had the 'guts' to pursue the affair as extensively as has been done in the 
last half year, if we hadn't had the notion that we could achieve 
something new.  As you say yourself, and we are of the same opinion, the 
value of the whole thing for us in regards to our own fabrication is not 
diminished by the abolition of the patent for the construction that is 
expected to be most feasable; only the expectation for good licensing fees 
has vanished.  By the way, if the newness is not questioned, we shall 
uphold our patent right, especially since the expenses for it have already 
been paid to a great extent."

The Zeiss field glass has the special advantage of creating an increased 
stereoscopic effect, thus an increased depth perception and a greater 
plasticity of the images, by the increased distance between the objectives 
in comparison to the distance between the oculars.  This is in addition to 
the advantage of being handy, which was achieved by the image erecting 
reflecting prisms, but the handiness was not patentable, after the patent 
office proved that it already belonged to the Porro telescope and was 
achieved by the same means.

But the other advantage, the increase of plasticity to nearly double, 
was founded in an idea that Helmholtz had developed in 1857 in a lecture 
about the telescope, but which had not been practically used, and it had 
not occured to anyone so far that it might be useable for the telescope.  
While Porro used his prism combination only to gain a monocular telescope 
of a shortened and handier form, Abbe united two Porro telescopes in a 
binocular telescope in such a way that the Porro prism combination not 
only shortened the tubes, but also separated the objectives to achieve an 
increased stereoscopic effect, and thus unite the two: the handiness of 
the binocular and the heightened plasticity of the images.

In the response to the patent office of December 21, the image erection 
was recognized as Porro's idea.  The new patent request was limited to 
image erection in connection with the increase in distance between 
objectives.  In regards to the previous patent application, the firm gave 
an explanation which begins as follows:

"The researches in the literature, caused by the declaration of the 
Imperial Patent Office of November 17, 1893, have confirmed that the 
Italian engineer Porro executed two constructions of terrestrial 
telescopes at the beginning of the fifties, and described them; so that 
the supposedly newly specified 4 times reflecting prism combination in the 
application, was already executed.  All reports to be found in the 
literature about the Porro telescopes are derived, as far as could be 
detected, from two reports which appeared in the years 1853 and 1856 in 
the French weekly Cosmos.  The first of these describes the telescope 
which is mentioned in Eisenlohr’s Textbook of Physics, first edition, page 
317, and pictured there, and which in the arrangement of the parts 
corresponds exactly to fig. 6 of the submitted drawing.  The other report 
gives a description of a telescope, where the reflecting prisms for 
reversal of the image are combined in the way described in fig. 7 of this 
drawing.

“Obviously, these inventions of Porro have not been successfully put 
into practice, and were therefore totally forgotten in practical optics.  
No mention is made of them anywhere in the literature on the subject; and 
among the textbooks of physics, that by Eisenlohr seems to be the only one 
that mentions the idea of Porro.  These circumstances will explain, and 
perhaps excuse, the fact that the patent applicant became aware of the 40 
year old work of Porro only after the report of the Imperial Patent Office 
gave a basis for the research in the literature."

On July 5, 1894 the requested patent was granted under the name: "double 
telescope with enlarged objective distance", whereby the increased 
plasticity was protected for 15 years.

It is interesting to learn that Abbe anticipated the possibility of 
failure for the first application and therefore divided the application 
into two parts, that of the image erecting prism combination and that of 
the enlarged objective distance.  The patent lawyer in Berlin who was to 
present the application proposed to Abbe that the application for the 
patent be formulated so that the second concept was included.  Abbe 
responded to that in a letter of September 6, 1893 as follows: "This 
second claim is, in regards to the first, totally superfluous and even 
pleonastic, if one considers the first claim as being totally assured.  
But we were motivated to add the second claim by the thinking of 'Ben 
Akiba', and we kept in mind the possibility that at some point an 
elementary school teacher may have expressed, even if incompletely, the 
prism combination described in claim one.  If that came to light after a 
year and a day, the patent, as far as it is based on claim one alone, 
could perhaps be invalid.  Thinking of this possibility was obvious, since 
the undersigned himself had already had this idea and already in 1873 had 
a small telescope of this kind built for his personal use.

“We believe it certain, that the other uses of the prism combination 
(namely the shortened tube length and the spacing of the objectives to 
achieve stereoscopic effects) will be totally new, even if the idea of 
image erection in the telescope by prisms should turn out not to be new.  
If somebody had recognized before us these advantages allowed by the prism 
system, this would have been noticed."

The Zeiss telescope was not only an economic success for the firm 
itself, but because of its advantages, it also inspired imitations by 
numerous other optical workshops.  This was made easier because only part 
of Abbe’s innovations were patented and the image erecting prism 
combination itself was not protected.  The outer form, handy and pleasing, 
of the Zeiss telescope prevailed over others, and the binocular replaced 
the monocular telescope which was common until then, the drawtube Dutch 
telescope.  In the following years there were attempts to eliminate the 
limited patent by lawsuits and to declare it null and void.  They tried to 
take advantage of the fact that at the time of the patent application the 
Porro system was not new; and that the publication of Helmholtz in 1857 on 
his telescope showed that when the two objectives had a greater distance 
from each other than the oculars, depth perception and the plasticity of 
the image was increased.  But these attempts were without success.  The 
Imperial Court said in its decision of March 26, 1898, among other things, 
the following:

"It is indisputable that the use of the Porro system in the binocular 
telescope, not only for image erection but also for increased stereoscopic 
effect by distancing the objectives in relation to the oculars, was new at 
the time of the patent application.  It is also no longer disputable, that 
by the combination as demonstrated in the patent application, for the 
first time a binocular telescope with stereoscopic effect was created for 
ordinary, and military, nautical and other uses, which could only be 
achieved without this combination by the doubling of the magnification of 
the telescope.  This doubling would make the telescope practically 
unusable for ordinary use.

“This obviously important economic progress suggests an innovation in 
the combination of the patent, not in a simple construction.
“Whatever the plaintif contradicts in this is not convincing.  It is 
correct that the accused achieves an already known effect in increased 
measure by means that were known individually.  Already known was the 
binocular telescope, the Porro prism system, and the idea of Helmholtz to 
cause the stereoscopic effect by enlarging the objective distance in 
contrast to the ocular distance.  But before the work of the accused, 
nobody had the idea that the image erecting Porro system in connection 
with the Helmholtz idea could serve to increase the stereoscopic effect.  
The invention is contained in this idea and its execution.  The allegation 
of the plaintiff, that this idea should have been obvious to any expert, 
has not only not been proven by the oral deliberation, but was 
contradicted by the facts in their entirety.  Both means were known to the 
highly qualified plaintiff.  But he didn't formulate the idea that the 
accused did.  Therefore the disputed patent has to be upheld."

Another large optical firm, which in 1897 followed the initiative of 
Zeiss in using the Porro prism in binocular telescopes, producing 
binoculars which corresponded precisely to the Zeiss model, but without 
the increased stereoscopic effect which was under patent protection, 
dared, in extensive announcements and cataloges, to direct the reputation 
among the public, for novelty and independent initiative, towards their 
own products, which Zeiss could correctly maintain for itself since 1894.  
The advantages of the terrestrial telescope with image erecting prisms 
were contrasted with the Galilean telescope, and it was advertised as 
their own new construction, though glossing over the fact that the new 
system was already on the market since 1894, and using words and 
expressions which were taken from the scientific publications of Zeiss.  
Zeiss sent out a withering circular against this behaviour, "For Defense 
and Clarification", of July 31, 1897, to their regular business customers, 
where the firm gave strong expression to its hurt feeling of justice and 
announced that it had begun the required steps for a charge of unfair 
competition and to ask for damages according to paragraph one of the law 
against unfair competition.  "We plan to resolve the affair with the 
fundamental question: whether the named law is only good enough to catch 
the little tricks of minor false sales, self-awarded exhibition medals and 
so forth; or if this law is also able to protect honest competition from 
the crafty and much more lucrative attempt, to guide foreign waters over 
their own mills, in grand style, which someone undertakes when, with his 
shabby harvest behind the achievements of others, he tries to brazenly 
usurp an aura of originality and well deserved progress, at the expense of 
others."

Zeiss obtained full satisfaction at the trial, since the Royal Court at 
Berlin on July 13, 1899, pronounced a judgement, confirmed on February 16, 
1900 by the civil senate of the Supreme Court, that: 1, the accused firm 
had to stop the further distribution of the catalogue in question, under 
penalty of 100 marks for each case of each violation.  2, that the request 
for compensation was correct.  And 3, that the plaintiff was permitted to 
publish judgement 1 in the appropriate journals within three months at the 
expense of the accused.

Only after the surmounting of many technical difficulties and the 
removing of some mistakes in the first execution, which happened thanks to 
the untiring efforts of Jakob Heckel, did Zeiss succeed in producing a 
really faultless precision glass worthy of the firm.  (*The difficulties 
which had to be overcome are very vividly described in the paper of the 
Supervisor, Ret., Ernst Michaelis (born January 12, 1867 in Rathenow, 
member of the firm April 17, 1891, pensioned May 5, 1932, reemployed 
October 2, 1939 to March 1, 1941)  "The First Field Glasses" in the Zeiss 
Journal of October 1941 is from his own experiences.)  The field glass 
reached the public market in the fiscal year 1894/95 with sales of 187,000 
Marks, this rose to 350,000 Marks in 1895/96, in 1896/97 to 548,000 Marks, 
and at the beginning of the new century surpassed the sales of microscopes 
and remained at the top, with both departments reaching the first million 
in sales per year.  Even after the expiration of patent protection in 
1908, field glasses, especially the 6 power and 8 power models, remained 
an important sales product of the firm, even though the other optical 
companies didn't miss the opportunity for sales.  Here as with the 
microscope, it can be seen how Abbe’s inventions were economically 
important, and what strong initiative they gave to the whole German 
optical industry.

During this time period, there was further development of the sighting 
telescope for rifles (1892) and for cannons (1894), the relief or scissors 
telescope, and the stereoscopic marine rangefinder.  All these instruments 
gained great importance and wide distribution in the following years.

In the time from 1846 to 1886, the little microscope workshop became a 
microscope factory, and during the decade between 1886 and 1896, by the 
incorporation of new and successful branches of production, the 
development was begun which led in the following half century to the vast 
enterprise of Zeiss, working in nearly all aspects of optics.  From the 
beginning to the end of this decade the yearly gross rose from half a 
million to 1,875,000 Marks, or by three and three quarters times; the 
number of employees and workers to the two and three quarters times; and 
the expenses for wages and salaries to the three and three tenths times.  
The firm with its 700 employees, to which were added the 250 of the Jena 
glass works, was already an important factor in the community of Jena.

As important as this time period became for the strengthening of the 
firm by the increase in production capacity, even more important for the 
future would be the fact that Abbe changed the privately owned firm to a 
foundation during this time.  We shall discuss this in future chapters, 
but first we shall become aware of the importance of the death of the 
founder of the firm, in whose honor Abbe named his great foundation.


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