The emergence of modern astronomy – a complex mosaic: Part IV

Another claim (that China teaching Europe printing technology) has turned out to be unsubstantiated.

The Renaissance Mathematicus

There is general agreement amongst historians of science that a major factor in the emergence of modern science in general and modern astronomy in particular was the (re)invention of moveable type printing and the arrival of the printed book in the middle of the fifteenth century. I say reinvention because moveable type printing emerged twice before in China in the eleventh century CE and in Korea in the fourteenth century, as I explained in an earlier post. For a long time it was a commonplace in the historical narrative that the printed book, like gunpowder and the compass, was a Chinese invention but extensive long-term research has failed to produce any evidence of a technology transfer and it is now thought that Johannes Gutenberg’s was an independent invention. Even within Europe Gutenberg was not the first to experiment with moveable type and his real invention was the printing press, inclusive…

View original post 1,415 more words

Sharpening a knife

Sharpening a knife.

by tonytran2015 (Melbourne, Australia).

Click here for a full, up to date ORIGINAL ARTICLE and to help fighting the stealing of readers’ traffic.

(Blog No. 1xx).

To be self-sufficient a person using any knife should know how to keep his tool sharp.

It is actually more involving than it appears and some people can not sharpen their tools while some other can do it extremely well. This blog gives an explanation to all this mystery.

Sharpening a knife.

#knife sharpening, #grinding stone, #aluminum oxide, #silicon carbide, #grinding stroke

1. Knowing the original capability of the tool.

The makers of tools usually know quite well how to bring out the best capabilities of their tools, a user can rarely bring any tool to a better state than provided by its maker when new.

For this reason it would be futile for the owner of a kitchen knife to attempt to make it as sharp as an expensive razor blade. If it can be done, the maker of the knife would have done it to advertise his products.

2. The material of a knife determines its practical sharpness.

2a- The sharpness of a knife depends on its materials. The materials of the knife blades are mostly metals. Any metal is made up of grains which adhere together firmly and closely. Atoms inside each grain arrange themselves into geometric pattern fitting the chemical bond configuration of the metal. The arrangement of atoms in each grain determines all (including physical) properties of that grain (For example, in one arrangement each atom may have twelve closest neighboring atoms while in another arrangement each may have only eight neighbors.). The bond configuration depends on and may even change drastically with the introduction of foreign (solute) atoms into the host (solvent) atoms of the grains. The change from one arrangement into another of atoms in a grain is called a phase transformation by metallurgists.

When metal solidifies multitude of crystallization centers form simultaneously and they are randomly oriented. Each crystallization center gives rise to one grain. The boundary of each grain is where its orientation is terminated by meeting different orientations from neighbor grains.

2b- If the grains cannot be shaped, cut and cannot adhere together to hold the shape of a thin edge then no thin knife edge can be formed. If the grains of a knife blade deform, crack easily or don’t adhere together there is no way of making a sharp edge for the knife. The boundaries between grains in a metal are the weak points of that metal. Cracks in a metal usually develop and propagate along grain boundaries. Corrosion also begins at grain boundaries.

2c- Any knife blade made of a single grain would be stronger and more corrosion resistant but it is uneconomical to make such knives from single large grains. Practical knife blades are made of metal with multitude of randomly oriented tiny grains. Finer grains give blades with better resistance to cracking.

2d- If the grains of a knife edge are heterogeneous then the blade can crack easily: Cast iron has heterogeneous grains and it is very hard to make any good cutting edge out of cast iron.

2e- When tougher grains of steel are gouged by the sharp particles of a grinding wheel their debris fly off at higher speeds. For this reason, high strength carbon steels give off the longest sparks when ground by a grinding wheel while mild steel and cast iron give off shorter sparks. For carbon steels knives it can be said that only blades that give off long sparks can make sharp knives (This observation does not apply to stainless steel knives as stainless steel debris don’t burn in air to make sparks).

2f- If the grains are flattened in the same plane as the knife edge then they can adhere together better: Forged knives hold their sharpness better than non-forged knives.

3. Application to the proper usage and care of knives.

Do not leave sharp kitchen knives made of high-carbon steel wet. Corrosion by water can damage it overnight resulting in the cutting edge being serrated.

Do let knife blades be heated to hotter than the temperature of boiling water or the temperature for causterization. Heating a knife edge may upset the structures of the grains in the blade. Razor blades are most susceptible to degradation by heat and will certainly become dull if heated by a naked flame. (High speed steel is the exception, its strength is not reduced even after it has been temporarily heated to high temperature. )

4. Sharpening of a knife edge.

The sharpening of a knife requires adherence to the following rules:

4a- Preserve the original shapes angles of the knives. The angles of the sharp edges have been chosen by the knife makers to give optimal sharpness and durability: Thin razor blades are sharp but are not impact resistant, thick axe blades are not that sharp but are impact resistant.

4b- When sharpening a knife blade, the grains of the sharpening stone should be finer than the required thin edge of the blade.

4c- All carbon and alloy steel tools can be ground and sharpened by Aluminum oxide sharpening stones.

4d- Quality alloy steel items (made of “tool steel” having higher hardness and can be used to cut other types of steel) such as “high speed steel” drill bits and lathe cutting bits should be sharpened by “silicon carbide” sharpening stones.

4e- Silicon carbide stones grinds ordinary steel much more slowly than Aluminium Oxide stones despite its grains of Silicon Carbide being harder than Aluminium Oxide. This is analogous to a 32 teeth/inch metal saw blade cutting wet timber much more slowly than a 6 teeth/ inch tree pruning blade

Applying higher pressure between a silicon carbide stone and the steel does not make the grinding any faster but make the binding matrix of the stone break and wear down the stone.

Therefore suitable (matching) type of grinding stones should be used for each type of steel.

4f- When proper sharpening stones are not available, they can be substituted by one of the following:

Any piece of hard stone with a flat surface with fine grain structure,

Any flat back of a hard ceramic tile.

Any flat bottom edges of ceramic drink cups or cooking bowls (however no lubricant should be used on these cups or bowls as it may contaminate food and drink prepared in them),

Any piece of abrasive paper wrapped around a firm flat surface.

4g- A liquid lubricant helps removing metal and stone debris from the grinding location and keep the grinding points cool. This makes faster grinding. Kerosene or light machine oil can be used as grinding, sharpening lubricant on proper sharpening stones. Using water as lubricant may cause corrosion on some types of steel.

4h. When sharpening the cutting edge of a knife by rubbing it against a stone that edge should be trailing behind the knife and kept at right angle to the direction of motion (the direction of the grinding stroke). Tiny grooves made at right angle to the cutting edge by this method of sharpening may serve as serration and may make the knife cut better.

Rubbing a block of cheese against a cheese grafter would give you some visualization of the effect of grinding steel grains against a sharpening stone.

Figure: Direction of grinding: The blade is rubbed against the sharpening stone by pulling it towards the user with his right hand; the small aluminium oxide sharpening stone is mounted on a flat plastic bar which is held by his left hand.

Figure: Direction of grinding: The blade is rubbed against the sharpening stone by pushing it away from the user with his right hand; the small aluminium oxide sharpening stone is mounted on a flat plastic bar which is held by his left hand.

4i. Pulling lengthwise the thin cutting edge of a sharp knife against a grinding stone will make it lose its shape and may destroy its toughness. Pulling lengthwise is only acceptable for axes and chopping knives with thick blades.

Pulling lengthwise against a sharpening stone may leave lengthwise grooves and lines of residual stress which may curl a thin blade.

4j. Circular grinding motion may be a compromise motion for sharpening a long knife blade.

4k. Sharpening by a powered grinding wheel may bring the steel of the knife blade to too high a temperature and may change its material as well as creating residual stresses in it. High speed steel is again the exception.

5. Conclusion.

Sharpening a thin knife is not hard and is a satisfying experience when adhering to all the above instructions.

Related HOW TO blogs:

Latest How to Blogs,

, , , , , , , Mung Beans as grains for self-reliance, Simple determination of East Asia lunisolar New Yearall



Click here go to Divider63D400 Home Page (Navigation-Survival-How To-Money).

SUBSCRIPTION: [RSS – Posts], [RSS – Comments]

MENU: [Contents][Blog Image of Contents ][Archives ] [About]

IPCC Pretends the Scientific Publishing Crisis Doesn’t Exist

via IPCC Pretends the Scientific Publishing Crisis Doesn’t Exist, Aletho News ΑΛΗΘΩΣ




Finding North from unclear sky around September.

Finding North from unclear sky around September.

by tonytran2015 (Melbourne, Australia).

Click here for a full, up to date ORIGINAL ARTICLE and to help fighting the stealing of readers’ traffic.

(Blog No. 1xx).

#find North, #finding North, #direction, #by stars, #Altair, #Fomalhaut, #September, #unclear sky,

Finding North from unclear sky around September.

Around September there are some bright stars shining the whole night. They include Deneb close to the Celestial North pole and Fomalhaut in the Southern sky. These stars can be used to locate the Celestial poles in the sky and subsequently the terrestrial principal directions.

1. Celestial poles and terrestrial directions.

Sun on Celestial Sphere

Figure: The Sun, the Moon and the stars are attached to a Celestial sphere which encloses the Earth like a giant rotating cage.

To an Earth bound observer, the Earth appears to be enclosed by a large rotating spherical shell called the Celestial Sphere with all stars attached to it. This shell rotates around the Earth nearly one revolution every 24 hous. This rotation leaves unmoved only 2 points on the shell. They are called the Northern and Southern Celestial poles of the Celestial Sphere.

If an observer can locate one Celestial pole then the projection to the ground of the line from him to the pole will be along his terrestrial North South direction.

2. Locating the Northern Celestial Pole in Northern hemisphere.

Figure: Polar Inversion map for the Northern Celestial hemisphere. The map should be read with its September marking on its rim pointing towards the ground as illustrated here.
An observer has to align the polar map with marking for September on the rim (at 6 o’clock position) pointing downward. An observer in Northern latitude above 30 degrees will see the rotation of bright stars Vega, Deneb [1], Cassiopeia constellation, bright star Capella then Big Dipper constellations in that order.

Cassiopeia goes highest around 01am.

The bisector of the M shaped Cassiopeia goes through the Northern Celestial pole. The Northern Celestial pole is almost 30 degree below Cassiopeia.

Sky map Northern 3/4 sphere

Figure 2: Polar Inversion map of Northern Celestial 3/4 sphere.

3. Locating the Southern Celestial pole in Southern hemisphere.

Figure: Polar Inversion map for the Northern Celestial hemisphere. The map should be read with its September marking on its rim pointing towards the ground as illustrated here.

An observer has to align the polar map with marking for September on the rim pointing downward as illustrated here. An observer in Southern hemisphere or on the tropical zone would see Achernar [1] rising highest around 2am. Southern Celestial pole is the midpoint of Achernar and the two Pointers and is about 30 degree from Achernar.

4. Locating the Celestial poles from tropical stars.

A observer in the tropic should already know the two brightest stars Scorpius Antares (at the heart) and Scorpius Shaula (at the stinger end) of the Scorpius [1]. The straight line from Antares to Shaula goes through the bright star Fomalhaut which is of 60 degree distances from both Scorpius Shaula and Altair [1] which is a star of July and is close to the Celestial equator.

Figure 2: The Mercator map of the sky for inhabitants of Tropical Zone. North direction is on its top. 24hr of R.A. is near the center and R.A. increases towards the left (East) of the map. The map is to be read South side up in the Southern hemisphere.

Figure: Fomalhaut and its nearby stars.

The bisector of the angle Shaula, Altair, Fomalhaut points to the Southern Celestial pole.

Southern Celestial pole is is of 90 degree distance from Altair and of equal 60 degree from both Scorpius Shaula and Fomalhaut.

5. Visibility of the stars.

Scorpius Altairs and Scorpius Shaula are stars of June that set close to midnight when viewed from tropical zone. Altair is a star of July that sets close to 02 am. Fomalhaut is visible for nearly the whole night in September.


[1]. tonytran2015, Finding North from unclear sky in April,, Finding North from unclear sky around July, posted on 2018, May 13.

[2]. tonytran2015, Finding North from unclear sky in April,, Finding North from unclear sky around April, posted on 2018, April 12.

[3]. tonytran2015, Finding North from unclear sky around New Year,, Finding North from unclear sky around New Year, posted on 2018, April 05.

[4]. tonytran2015, Finding North and time by stars,, Finding North and time by stars, posted on August 28, 2015

[5]. , posted on

[6]. The Orion constellation., posted December 26, 2016

[7].The Scorpius constellation., posted January 8, 2017


Caution in finding North by bisector line of a horizontal watch. Posted on October 28, 2015

Finding directions and time using the Sun and a divider., posted on May 6, 2015. <<<—This is my MOST USEFUL novel technique.


find North by the Sun

Finding North direction and time using the hidden Sun via the Moon . Posted on July 6, 2015


Finding North direction and time accurately from the horn line of the Moon. Posted on August 12, 2015. This is my novel technique.


Finding North direction and time using the Moon surface features. Posted on July 1, 2015.


, posted on

Finding North and time by stars. Posted on August 28, 2015

Sky map Northern 3/4 sphere

Sky map Southern 3/4 sphere

Finding North and time with unclear sky. Posted on October 17, 2015.



, posted July 22, 2016


Click here for my other blogs:



Click here go to Divider63D400 Home Page (Navigation-Survival-How To-Money).

SUBSCRIPTION: [RSS – Posts], [RSS – Comments]

MENU: [Contents][Blog Image of Contents ][Archives ] [About]

The Frog and the Scorpion

via The Frog and the Scorpion

(reblogged from )

Illustration image from:

One day, a scorpion looked around at the mountain where he lived and decided that he wanted a change. So he set out on a journey through the forests and hills. He climbed over rocks and under vines and kept going until he reached a river.

The river was wide and swift, and the scorpion stopped to reconsider the situation.

He decided to ask the frog for help getting across the stream.

“Hellooo Mr. Frog!” called the scorpion across the water, “Would you be so kind as to give me a ride on your back across the river?”

“Well now, Mr. Scorpion! How do I know that if I try to help you, you wont try to kill me?” asked the frog hesitantly.

Halfway across the river, the frog suddenly felt a sharp sting in his back and, out of the corner of his eye, saw the scorpion remove his stinger from the frog’s back.

“You fool!” croaked the frog, “Now we shall both die! Why on earth did you do that?”

The scorpion shrugged, and did a little jig on the drownings frog’s back.

“I could not help myself. It is my nature.”

Then they both sank into the muddy waters of the swiftly flowing river.

Self destruction – “Its my Nature”, said the Scorpion…

Comment by tonytran2015:

Never compromise your own survival to be helpful to strangers or acquaintance. The world is quite treacherous.

See also:

RELATED Social Issues Blogs


magnifier horizontal







Latest Social Issues Blogs,

, , ,

Click here for my other blogs:




Click here go to Divider63D400 Home Page (Navigation-Survival-How To-Money).

SUBSCRIPTION: [RSS – Posts], [RSS – Comments]

MENU: [Contents][Blog Image of Contents ][Archives ] [About]

Indian mariners had first use of magnetic navigational compasses.

Indian mariners had first use of magnetic navigational compasses.

by tonytran2015 (Melbourne, Australia).

Click here for a full, up to date ORIGINAL ARTICLE and to help fighting the stealing of readers’ traffic.

(Blog No. 1xx).

The magnetic navigational compasses may have been first used by Indian people and may not have been first invented by Chinese people as often claimed.

#compass, #navigation, #lodestone, #Chinese compass, #Olmec magnetic, #Indian, #yantra, #matsya yantra, #maccha yantra,

Indian mariners had first use of magnetic navigational compasses.

1. Claims that China invented the compasses.

Wikipedia said that

“The first compasses were made of lodestone, a naturally magnetized ore of iron, in Han dynasty China between 300 and 200 BC.”[1]

The entry on Han Dynasty said that

“The Han dynasty (/hɑːn/; Chinese: 漢朝; pinyin: Hàn cháo) was the second imperial dynasty of China (206 BC–220 AD).” [2]

Figure: Han Dynasy, from

So the compasses are used in China after 206 BC, but it was initially only for geomancy.

“The magnetic compass was not, at first, used for navigation, but for geomancy and fortune-telling by the Chinese. The earliest Chinese magnetic compasses were possibly used to order and harmonize buildings in accordance with the geomantic principles of feng shui.” [1]

“The compass was later used for navigation by the Song Dynasty”[1]. (Song Dynasty: Chinese: 宋朝; pinyin: Sòng cháo; 960–1279)

So the written records on the use of compasses for navigation in China are made after year 960 CE.

Note that there were South-pointing chariots used in ancient China before year 235 CE [2b, 2c, 2d] but their operation was not based on magnetism. Their operation relied on the differential between the numbers of rotations of the left and right wheels (of same size) of each chariot to give its total yawing angle since departure.

Those chariots may have even been “first constructed by the Duke of Zhou (beginning of the 1st millennium BC) as a means of conducting homewards certain envoys who had arrived from a great distance beyond the frontiers.” [2b].

Figure: Model of a Chinese South Pointing Chariot, an early navigational device using a differential gear. Original file from
by Author Andy Dingley, licensed under the Creative Commons Attribution 3.0 Unported license.

2. Appropriate places to look for records.

Many people look for easily read records. China certainly has many records which have been translated into English and are easily understood by readers in the World.

However, China is a land conquering empire, requiring little use of compasses while India is a sea faring trading empire which may benefit a lot from compasses. The logical place to look for records of first use of navigational compasses should therefore be India, an outreaching seafaring trading empire (as necessity is the mother of inventions). Indian influence is obvious over the vast area of Indian Ocean, Polynesian nations and (mostly South) Pacific Ocean [2e].

Any discovery of earlier use of magnetic navigational compass predating Chinese use should not surprise/disappoint investigators as the people of the trading Olmec nation (on the side of the Gulf of Mexico) has even used lodestones, hematite, magnetite since 1500 BC, one thousand year before any record of Chinese first use of lodestones [3], [4].

It is to be noted that China is on the East of India while Arab countries, Spain, Olmec are spread to its West.

3. Many evidences pointing to ancient use of compasses by Indian people .

The literature of the out reaching, sea faring nation India have many evidence to support its first use of the magnetic navigation compass.

“The compass was first used in India, around 1800 BC, for Navigational purposes and was known as “Matsya yantra” (which roughly translates to fish machine) because of the placement of a metallic fish in a cup of oil.” [5]

However, no evidence have been given in [5] to support the claim of “around 1800 BC”.

Reference [6] stated that
“In the Tamil nautical books, the use of compass is mentioned in the fourth century BC”,

4. Evidence on knowledge of magnetic attraction by Indian people since 500BC.

K. V. Ramakrishna Rao [7] pointed out that:

In Vedas, there is reference to “ayas” implying Iron and “Akarshan” attaction, thus, pointing to Iron-magnet relationship.[7]

Kanada (c.550 BCE) mentions about a needle that moves towards a magnet as –

“Manigamanam sucyabhi sarpanam drastakaranam” (Kanadasutra.V.I.15). In the commentary called the Upaskara, the passage has been clearly explained to signify that the needle goes towards the magnet.[7]. (Wikipedia [8] stated that Kanada was estimated to live between 6th and 2nd century BC.)

Kalidasa (c.500 BCE) records: “Siva’s mind has been fixed steadily because of penance. And therefore, now try to distract his attention just like an iron piece is attracted or drawn towards a magnet (ayaskantena lohavat akarshtum)” (Kumarasambavam.II.59).“[7]

The date of 500 BCE assigned for Kalidasa quoted by [7] may be in error. Wikipedia [9] stated that Kalidasa’s works cannot be dated with precision, but they were most likely authored within the 4th-5th century CE. In any event, it is not important, only the date of 550BCE assigned to Kanada is pivotal to the thesis of this article.

5. Evidence on compass use by Indian people since 500CE.

Milindapanho (VII.2.16) composed during 4th-5th centuries CE, mentions about an instrument used by the pilot of a ship for steering the ship.

“And again, O King, as the pilot put a seal on the steering apparatus, lest any one should touch it”.

Rhys Davis translates the term as “steering apparatus” and it Sanskrit it is “yantra”, a mechanical devise, just like “matsya yantra” working on mechanical and accompanied with other principles.[7]

Mookerji points out a compass on one of the ships in which Hindus of the early Christian era sailed out to colonize Java and other islands in the Indian ocean. The Hindu compass was an iron fish (called in Sanskrit matsya-yantra or fish machine). It floated in a vessel of oil and point to the north (History of Indian Shipping, London, 1912) [7].

The following is what Mr. J.L. Reid, who was a member of the Institute of Naval Architects and Shipbuilders in England, has said in the Bombay Gazetteer, vol. xiii., Part ii., Appendix A.

“The early Hindu astrologers are said to have used the magnet, in fixing the North and East, in laying foundations, and other religious ceremonies. The Hindu compass was an iron fish that floated in a vessel of oil and pointed to the North. The fact of this older Hindu compass seems placed beyond doubt by the Sanskrit word Maccha Yantra, or fish machine, which Molesworth gives as a name for the mariner’s compass”. [10]

6. Conclusions

The thesis of this article is Indian mariners have already used magnetic navigation compass at least since 500 CE while Chinese had recorded usage of them only after 900 CE, a long four hundred years later.

It appears that the out reaching Indian seafarers had the first use of magnetic navigational compasses. Since necessity is the mother of inventions, it is natural to expect this as India had been an ancient seafaring trading nation.




[2b]. Needham, Joseph (1986). Science and Civilization in China: Volume 4, Part 2. Taipei: Caves Books, Ltd., pages 286, 289, 291, 298.








[5]. .







RELATED Survival Blogs

Finding north with a lensatic compass, posted August 21, 2017,

How to Blogs

Rice as emergency food., posted December 24, 2016, Mung Beans as grains for self-reliance. , Dried sweet fruits as energy food ,

Latest Social Issues Blogs
, , , ,



Click here for my other blogs on SURVIVAL

SUBSCRIPTION: [RSS – Posts], [RSS – Comments]

MENU: [Contents][Blog Image of Contents ][Archives ] [About]

Who Survived More Lightning Strikes, Roy Sullivan or Melvin Roberts?

Reblogged by tonytran2015.

Source: Who Survived More Lightning Strikes, Roy Sullivan or Melvin Roberts?

Related blogs

True Strange Library

Today’s stop on our world tour of true strange stuff: two “human lightning rods.” The first isRoy Sullivan, a bear smacking park ranger who survived being struck by lightning seven times. Who else ever (quite reasonably) kept a bucket of water handy in his truck for when his hair caught on fire?

Roy Cleveland Sullivan (February 7, 1912 – September 28, 1983) was a United States park ranger in Shenandoah National Park in Virginia. Between 1942 and 1977, Sullivan was hit by lightning on seven different occasions and survived all of them. For this reason, he gained a nickname “Human Lightning Conductor” and “Human Lightning Rod”. Sullivan is recognized by Guinness World Records as the person struck by lightning more recorded times than any other human being.In [a] photo of him … a prominent burn mark is visible on his ranger hat.


The details are an astounding…

View original post 1,853 more words

42,000-year-old worms revived from Siberian permafrost

Lives from different periods of time can intermingle. How can you be sure that you are older than all the worms around you ?


Well, it looks like you can’t just freeze politicians and end their reign of terror. It turns out, they might still be thawed out 42,000 years later beginning again. The latest biology news was reported in Germany in A 42,000-year-old soil sample from Siberian permafrost contained nematodes. It was thawed and the soil contained worms which were brought back to life. This amazing event set the biology record for the period of time over which higher organisms can survive in cryogenic sleep. They reported that the worms began to move within a few weeks at 20 degrees Celsius in the Moscow laboratories and began to eat food.

There are two species of worm that have been discovered. Panagrolaimus nematodes have been revived which date back 32,000 years and were located at about 3.0 meters down. The Plectus worms were discovered…

View original post 46 more words