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Little lenses

Posted by jholmes61 on February 25, 2018
Posted in: Uncategorized. 1 Comment

Last week was a “little lens” frenzy. It started out with a coworker asking me if I had a Leeuwenhoek style microscope that they could borrow for a Museum program. That pushed me to finally give it a try. It turned out that I had all of the materials, so I got started Thursday night at Microscope Makers night. I got the two plates rough cut and hammered to give them a hand worked look. Doesn’t quite look like the Leeuwenhoek microscopes I have seen, but I do like the look.

Then Friday evening I worked on the main positioning screw. I was working with some rod that was a little large in diameter so I machined it down a little. Then used a die to thread it. The closest one I had on hand was 6-32. I filed the end instead of hammering it flat.

I liked the look. I didn’t want to mess it up, and timing was going to be tight with needing it for the Museum program so I went with the filing.

Saturday was the big work day. I had some bead lenses that I had made a few years back, but they were not as round and larger as I was hoping for do I got out the torch.

It was a little tricky taking the photos and working the glass so the photos are not the best…

Then shaping the brass plates. I super glued them together for the cutting, filing and drilling, then a little heat on the stove popped them apart:

There is a 1/8 inch diameter ball bearing that I used to make the dimple in the brass. Bearing in the middle, sandwiched between the brass plates at the drilled lens hole, and that between two fir blocks, end grain towards the brass. This was then smacked with a hammer about 4 times.

I sanded the inner surface of the brass plates to take off some of the larger bumps from the hammering.

Next was the bracket, focusing screw, attachment screw and specimen mounting pieces.

Then hammering the rivets. For this and the initial hammering of the flat metal I used a cleaned up piece of leaf spring as an anvil. The leaf spring was found by the side of the road on a hike earlier this year.

Taping all the holes, and putting the parts together, here is what I have, finished that Saturday evening.

I tested it out with a few strands of feather. The focal length is pretty short! I’ll check the magnification soon.

I did use a few websites for guidance. For measurements and general construction I used Alan Shinn’s piece:

http://www.mindspring.com/%7Ealshinn/Leeuwenhoekplans.html

For making the lens I followed Professor Keeling’s procedures, nicely updated with some video now:

http://www3.botany.ubc.ca/keeling/microscope.html

After the excitement of completing the Leeuwenhoek – like microscope (a few modifications, but in the spirit I think, and it does seem like there is a bit of variability in size and design of the scopes that Leeuwenhoek made, so I think the personal touches are ok.), I got to thinking about the Foldscopes that I recently received. They are actually a very similar concept to the Leeuwenhoek microscopes, a single lens mounted in a handheld focusing device that is held up to the eye. A teacher friend who had also received her Foldscope had sent out a note asking if anyone had assembled one. So on Sunday morning I took one of mine over to the Chipped Cup cafe across the street, got a mocha and some breakfast and got to work!

I took one of the student kits, very compact, just the scope, not all the extra collection and lighting gear of the Deluxe Kit. Save that fun stuff for later. I unfolded the directions and spread out the parts and got to work!

The directions are very well done, but it is very important to pay attention to which side is up, on both the magnets and the parts. For the magnets there is a silver side and a black side and all of the “paper” parts are printed with different colors on opposite sides so just pay attention. I had to backtrack a couple times but it all worked out in the end.

The above was one of my oops moments. See the picture on the paper and the object in my hand do not match. I popped the magnet holder out, flipped it around and was back on track. (shown below).

The whole assembly was less than an hour, with mocha.

I went home and assembled one more.

Now a group of us are talking about getting together and experimenting to develop our Foldscope skills in preparation for the warm weather and Leeuwenhoek Day, September 7th, 2018!

This was my first photo through the Foldscope. I chose a flea in honor of one of Robert Hooke’s famous drawings from Micrographia.

NYC Echinocystis Expedition 3

Posted by jholmes61 on February 4, 2018
Posted in: Uncategorized. Tagged: botany, climbing plants, Darwin, Echinocystis lobata. Leave a comment

On October 7th, 2017 I went on a third NYC Echinocystis Expedition. This one to Van Cortlandt Park in the Bronx, a quick trip to the end of the 1 subway line. I covered a lot of ground looking around the lake, marsh and stream areas where it was a little damp, looking for something similar to the New York Botanical Garden site by the Bronx River.

Not finding anything there I headed off into the woods. No particular destination in mind, but an eye out for damp spots.

There are some great trails in Van Cortlandt Park and many with very light traffic. On my big loop through the woods, I only saw two other people when I was off the main trail. The forest is nice, lots of large oaks, a few black walnut, cherry, tulip tree, and other hardwoods. Lots of non-native stuff, including a little Common Toadflax, Linaria vulgaris, another plant that Darwin studied.

I was coming around the bend and starting my way back when I saw a grove of jewelweed or as we called it where I grew up, touch-me-not.

That second name refers to the response of the seed pod when ripe. 🙂 the flower is very showy orange with spots and a nice spur with nectar for the likes of hummingbirds.

The Echinocystis lobata at NYBG were growing over jewel weed, and there it was! The wild cucumber climbing over jewelweed again!

This patch with some very impressive fruit.

And flowers

Echinocystis lobata has both pollen producing “male” and ovule producing “female” flowers at the same time, this is called synchronously monoecious. The snowflake like flower above is a pollen producer.

This photo has both, the female flower has dropped, and the developing spiny ovary can be seen.

There were many other plants in the mix: American Pokeweed and Norther Spicebush around the edge, English ivy under neath and false nettle, white avens and others mixed in.

Above some Echinocystis lobata tendrils cling to a Spicebush. Some of the Spicebush leaves had some irregular central patches with brown centers and yellow rims…

…on flipping the leaf I found the cause, the Andromeda Lace Bug seen in the photo above. The black spots are droppings. Molts of the nymph stage were visible on the midrib of the leaf. I have seen these guys on Spicebush in Central Park as well.

I did not find any opened fruit at this site. After having fun photographing a jumping spider and the plants I moved on.

I was just using my phone to take the photos today, and it was getting a little late and dark so some of these photos are a little grainy.

I started my journey back to the 1 Train and found another patch of Echinocystis lobata!

This one with some ripe fruit that had opened up. One still had a seed wedged in the pod.

The seeds are quite large and have a two tone brown coloration. This was fun! Two patches of the plant that Darwin studied, growing wild in New York City! I continued on down the bike path and passed some other climbers, here are two, greenbrier (glossy oval leaves) climbs with tendrils and the moonseed with the slightly lobed leaves wraps its stem or twines as it climbs over the greenbrier.

There was also lots of poison ivy, porcelain berry, autumn clematis, and Virginia creeper. It was a great day for observing climbing plants in New York City!

Going to press

Posted by jholmes61 on February 4, 2018
Posted in: Uncategorized. Tagged: botany, Darwin, specimen preparation. Leave a comment

Busy Fall, too many fun projects.

So, when last we spoke, the time before last actually, I was on the trail of wild Echinocystis lobata in New York City, and David Atha from the New York Botanical Garden offered to host me to see some growing on their grounds.

We found some, and I was able to take some time-lapse photography of the circumnutation! Too much fun, but it does get better! Daniel collected an Echinocystis lobata specimen for the NYBG herbarium! He gave me permission to share photos of the process here!

Data is a very important part of any scientific specimen, the more data the better! These days location data is very easy to gather, since many phones include GPS chips.

Data is recorded in a field notebook. Specimens are given a field number by the collector. This is usually a serial number starting with your first scientific specimen being #1 and counting up from there. It will get an institution number when it is delivered to the collection. Date, time, location, collector, those in the collecting party, description of the habitat including associated species… anything that might deepen our understanding of the plant and variables that might affect it and that it might affect.

The specimen is placed between newsprint which is between two sheets of blotting paper which is between two pieces of corrugated cardboard. This is usually within a stack of several specimens which are strapped together between two stiff wooden frames to hold them flat. The whole bundle with frames and straps is called a plant press.

This specimen was in fruit, and the fruit was rather large, so in order to make the internal structure visible in the final specimen, and to aid drying, the fruit was sliced and arranged with the specimen.

The arranged specimen, with some leaves set to show the dorsal surface and others to show the ventral is sandwiched between all those layers and dried.

Later it will be attached to an “herbarium sheet” with a label and added to the herbarium collection.

This specimen will eventually be listed in NYBG’s C. V. Starr Virtual Herbarium! It isn’t there yet, but soon I hope! Once it is I will add a link to its online record.

Thank you to Daniel Atha and NYBG for sharing this process with me, and letting me share it here!

Workin’ on Low Mag

Posted by jholmes61 on November 3, 2017
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Just a quick update on lens work.

In thinking about Darwin and his backyard, thank you Jim Costa, I am feeling the need for a lower magnification lens for looking at plant parts, and maybe some insects. This goes back a little ways, but sometimes it takes a while to get up a head of steam. I purchased a one inch diameter ball nose mill last year. Which is kind of like a one inch diameter drill bit with a round end on it instead of pointy. This is a pretty big hunk of steel. The little lens lap disks that I have been making are too small to hold and bare down on with this fat mill tool, so I needed to make a bigger lens lap that would have a base the would fit down into the smaller holder that I have been using. 


I make these with cast iron. I faced the end, then brought the general diameter down, back about to the chuck jaws, then reduced the diameter to fit into the lap holder fixture that I already have. 

Dinner break at the #harlempublic NYC with a #Longtrailbrewery IPA, go Vermont!!


Back. Then cut off the part. 


And this if how it looks in the lap holding fixture.


Next step, figure out how to hold a 1 inch ball nose mill on a Sherline lathe/mill (I am using a lathe with a vertical milling column).  This ball nose mill is BIG. I eventually discovered Sherline sells chuck blanks!! So I got one and got boring! 😉 


Well drilling first. Using a center drill, then about 5, gradually larger, drill bits. THEN boring. 


Then a set screw hole to keep the milling tool from slipping.



Add some threads with a tap.


Then check it all out in position.


Yikes! I hope I can drive that with the Sherline! 

So I used a wiggler to center the mill on the cast iron lap.


Then switched in the one inch mill, and after a bit of chatter and some speed adjustments, I got the spherical depression to the size and finish I wanted.


So many parts to get to where you want to be!


Here we are with the tool ready to grind a lens.


So, some glass… I sorted through my collection, some are fun older pieces, but in looking at them with a loupe, 

they have some bubbles.

So I landed on a piece of glass from my sister’s neighborhood in Columbus, Ohio and started shaping with a glass cutter and pliers. 


I am shooting for about 0.4 inches in diameter and .08 inches the (that Pythagorean Theorem is amazing!)

Then using the grinding wheel on a power drill I got it down to a size to fit into the lap last night. 


And tonight I got to grinding. This bigger lens is a bit different from the small ones. It tends to chatter more easily. A bit more water seems to help with that. The chatter can send a bit of vibration through the lens… then pop!


Ouch! Not personally “ouch” but emotionally…


The vibration popped a pretty good chuck off the side of the lens blank! Darn it! Well, I guess this happens. The grinding with the drill probably creates a few fractures around the edge, and the chatter in the lap can be a pretty sharp shock… and in the right place, fractures propagate.

I think I knocked off a bit more diameter that I can be happy with. I’ll measure it up, and think about what to do next, but at the moment I think I will have to make a new lens blank with a new piece of glass. I’ll have to try another visit to Columbus for glass for a different lens, although I think I do have another Columbus piece… it is pretty thick, too thick for this lens, but maybe another…

The Wild Cucumber in New York: Part Two

Posted by jholmes61 on October 9, 2017
Posted in: Uncategorized. Tagged: botany, climbing plants, Darwin, Echinocystis lobata. Leave a comment

Upon returning from the first expedition with an expanded understanding of NYC native climbing plant diversity, the search for Echinocystis lobata continued. The e-mail conversation expanded as the CC list grew. Daniel Atha the Director of Conservation Outreach at the New York Botanical Garden joined the thread. The possibility of exploring sites at NYBG came up. There were reports of E. lobata being there, including an iNaturalist sighting. Daniel also helps coordinate the  New York City EcoFlora project which “is designed to serve two complimentary purposes: (1) to meaningfully engage New Yorkers in protecting and preserving the City’s native plant species, and (2) to assemble new, original observations and data on the City’s flora to better inform policy decisions about management and conservation of the City’s natural resources.”  The Project uses the iNaturalist platform as its citizen science platform, it is great fun, join in! Daniel invited me up for a day of wild cucumber searching. With a goal of recording a time-lapse video of circumnutation in the wild. We planned a visit for September 17th and met at the Watson Building on a mild, calm, overcast day.

The iNaturalist sighting was right on the trail at the north end of the Thain Family Forest along the Bronx River. We headed straight for the spot, and there they were!


Draped over the split rail fence, and below in the shade of maples and cherries climbing over some 5 foot tall Jewelweed (Impatiens capensis) and nettles. We explored the area to find the best photo op. The area had quite the collection of climbers, the native Sicyos angulatus, the oneseed bur cucumber, was there, and doing very well. There were a few non-natives: Japanese Hops, (Humulus japonicus) and —- Porcelain Berry, (Ampelopsis brevipedunculata). We found some E. lobata on both sides of the river, but mostly on the lower, cooler, west side of the stream. The Echinocystis seems to prefer the cooler damp spots, generally not so much direct sun as the Sicyos angulatus seems to tolerate.

We had a great time, I set up the tripod with my iPhone using the app “Timelapse” to capture a video of the movement for one hour at a sped up rate of ten times normal. The app does a great job.

Post time-lapse video here.  

Video taken in the Thain Forest, New York Botanical Garden by Jay Holmes © 9/17/2017

Daniel worked on locating and collecting an herbarium specimen of Echinocystis lobata for the NYBG collection.

Photos of plant collection coming soon

In search of the Wild Cucumber in New York City

Posted by jholmes61 on October 8, 2017
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A group of us are working on a teacher course around some of the experiments that Darwin conducted in his garden. 

Darwin was a communicator! Involved in a wide network of correspondence with fellow countrymen as well as all sorts of people around the world. Gardeners, orchid growers, and scientists. He did have some friends in our area, and through this connection had exposure to some of our native plants, some of Darwin’s local plants have found their way over here and are now sprinkled about our landscape. In preparation for the course next Spring, I started wondering if I could find some of these plants in convenient locations in New York City.

His activities around plant movement and climbing plant in included a North American plant, Echinocystis lobata, the Wild Cucumber.  This tendril baring climber with light green leaves which look a lot like sweet gum tree leaves, produces similarly light green, kiwi sized fruit covered with 1/4 inch (0.75 mm) long spines. The fruit hang like Christmas ornament from the climbing vine. They bare “male” pollen producing flowers which are like little six petaled snowflakes, and “female” flowers with the little spiny ovule. 

I have been trying to germinate some this year, but have not been having much luck. I stratified the first round of seed for a couple months, then got some fresh seeds from another supplier, I tryied chipping the seed coat… then I did some deeper research… hmmm I know, a little late…  and I found this!

Dormancy and germination in seeds of Echinocystis lobata. CHOATE, Helen A., Smith Coll., Northampton, Mass., American Journal of Botany 1940 Vol.27 pp.156-60.

A – someone actually did this research, B – someone from Smith, my sister’s alma mater, as a kid I loved to visit their greenhouse, and C – a tip! Stratification time is much longer than what I was trying… 21 weeks gives 80% germination rates! Less than 20 weeks gave much lower rates. And the stratification temperature should be 5-10 degrees C…. good data… now I’m moving forward with those guidelines. 

While I’m waiting for 20 weeks to pass, I am interested in finding some local populations. I put out the idea to some friends at the botanic gardens in the City and jumped online again. Barbara from BBG jumped in with some references to some sites including NYBG in the Bronx. I ran across  this report: 

Natural Area Mspping and Inventory of Highbridge Park by the City of New York Department of Parks and Recreation https://www.nycgovparks.org/sub_about/parks_divisions/nrg/documents/Ecological_Assessment_Highbridge_Park.pdf

It listed Echinocystis lobata! I had seen E. lobata when I was growing up in Massachusetts, growing in damp areas, so I headed for the lower areas of the park looking for moist spots. 

I went from 155th Street, east to Harlem River Driveway down to Harlem River Drive. I didn’t have any luck. I periodically detoured into the woods. Damp, yes, other climbing plants; poison ivy, Virginia creeper, waves of porcelain berry, and some Jewelweed… I got almost to the base of the old aqueduct bridge, and there, creeping across the side walk! Light green tendril baring vines with maple like leaves, and some little developing flower buds! In my excitement I whipped off an e-mail from the field! Wild cucumber located in Highbridge! Climbing over the Jewelweed, over the ground and up an oak tree!


I continued on exploring in hopes of seeing some Wild Cucumber fruit of Echinocystis! Passing under the great arching aqueduct, entering a little construction zone where they are fixing up trails and paths in this lower section of the park. Then just north of the aqueduct the path takes a turn up the hill. The construction has included a chainlink fence… which seems to make a wonderful trellis.


And there it was, more light green tendrils, this time with open flowers! But they didn’t look like what I was expecting… these had 5 wide petals… something was a miss! I didn’t notice any big cucumber fruits. There was a bit of nectar collecting going on, a bald faced hornet. I only saw one at a time.

There were many of these vines climbing the fence and the trees along the path for about 200 meters as it slowly climbed the grade. They don’t over take an area like porcelain berry. There were a couple that had grown up small trees abou 6 meters high, and were dangling down about 2-3 meters from the branches. This area was a little more sunny than the first spot under the large oak, and these vines had many more flowers. Perhaps the extra sunlight had something to do with that. There seemed to be some water trickling out of the rocks under the highway ramps. There were lots of pokeweed and Japanese Knotweed that the vines were climbing over as well. After about 200 meters the porcelain berries came to dominate and no more light green vines from there on up the hill. Perhaps it becomes too dry for them.

I continued up the hill, and hiked over the aqueduct to the Bronx side. I did not see any of the light green vines on the Bronx side. The area seemed pretty over run with porcelain berry. 

Once I got home and started uploading my plant observations to iNaturalist and doing some research I came to the conclusion that I had seen Sicyos angulatus, no Echinocystis lobata. The Sicyos angulatus leaves are less deeply lobed and a little less glossy. The flowers only have 5 petals and those are much broader. They are in the gourd family still, but their fruit is much smaller and bare only one seed each. 

So the hunt for Echinocystis lobata, the Wild Cucumber, in the wilds of New York City continues.

Scoping out my #VanLeeuwenhoekDay destination 

Posted by jholmes61 on September 6, 2017
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I will be headed to the Lake in Central Park tomorrow. It is looking pretty green right now which is a good sign for our Cyanobacteria hunt.


It is a little cool, damp and overcast today, but Thursday is looking better, at least not damp. 

To get to this spot I’ll be leaving the Museum of Natural History, past Alexander von Humboldt…



And through Naturalist Gate!


I love this plaque! 

I have also been thinking about Van Leeuwenhoek’s microscope, if you are interested in replicating his tools and technique, the page by Dr Patrick Keeling is a great guide:

http://www3.botany.ubc.ca/keeling/resomicr1.html

My one tip is when pulling the glass fiber use a quick motion. Once it softens, just PULL FAST to make a nice thin thread/tube.

I have some of these left over from a previous activity that I might try. 

Next year I’ll have my Foldscope, which is not all that different from Leeuwenhoek’s microscope, concept wise. I should try my hand at making a brass Van Leeuwenhoek microscope… 
Anyway keep pulling your stuff together. Droppers, nets, slides, cover slips…

Van Leeuwenhoek Day!

Posted by jholmes61 on September 6, 2017
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Thanks Wim for the banner! I’m getting ready for Van Leeuwenhoek Day  2017! I have my scopes in the office.


A Bancks from 1825, an Holmes from 2014 and an unsigned folding scope from the 1880s or so. I have that one for photography. I will be using the first two as single lens microscopes, Leeuwenhoek used a single lens of course!

I’ll be going to the Lake in Central Park, New York City, New York for my expedition.

 The weather is looking ok here:


For a little background on the story:

So, the Internet is a wonderful thing… I sent a little e-mail to some friends and it seems to have generated a some interest. So I thought I would share this more widely and see what happens. I would like to say that this is just for fun, nothing big and organized. But I will try to provide a little more detail for those who would like that.

For sharing purposes you can share your photos via Twitter, Instagram, Facebook… with posts containing the hashtag #VanLeeuwenhoekDay (sorry, I know that came out long…)

When you post your photos include where you went, town/city, Sate, Country and water body… and anything you saw. Keep it brief.

If you want to see all of the shares on all of these platforms after the Van Leeuwenhoek Day I think you can got to https://www.hashatit.com/ and search for “#VanLeeuwenhoekDay”

Or you can do an individual search on each platform: Facebook, Twitter, Instagram,…

Why Van Leeuwenhoek Day?

This is a note that I got from a friend, Wim van Egmond, from the Netherlands last year at this time that explains this day (another amazing thing about the Internet, friends everywhere!):

“Today it’s Van Leeuwenhoek Day! The day the Berkelse Mere letter was written by Anthoni van Leeuwenhoek. In a letter dated September 7, 1674 he wrote about the organisms he found in water taken from the Berkelse Mere. Observing the water through his little microscope he discovered the micro world. What he described was a cyanobacteria bloom containing what we can now identify as Dolichospermum, a planktic type of cyanobacteria that forms helical chains. In the letter there are so many clues (green tendrils coiled like the copper snakes used by distillers, made out of little balls) that it is very probable this is what he saw.

It is not possible to put names to the other organisms he observed but these were most likely rotifers, several kinds of single celled algae like euglenophytes, green algae and other flagellated forms. These are the most common organisms in the type of water he found and they fit the description. He writes about an ‘egg-round’ organism with legs on its head and fins near the tail. This could very well be a rotifer but it is hard to say which one. Another organism is a bit longer than an ‘egg round’ and moves slow. I can’t think of any other organism than the rotifer Asplanchna.

Since the Berkelse Mere letter can be regarded as the birth of microbiology I would like to propose to celebrate this day as Van Leeuwenhoek Day. Perhaps we can turn it into an annual event.
I am doing a bit of research about the find because I live at the location of the former lake. You can read a bit more about the find in the Micscape article: http://www.microscopy-uk.org.uk/…/artf…/wimleeuwenhoek2.html ”

Thank you Wim for the inspiration!

Wim does some amazing microphotography, here are some of his Nikon Small World entries:

http://www.nikonsmallworld.com/people/bio/wim-van-egmond

He has done some recent work around soil communities, fun stuff!

So. If you want, go out to a pond with any kind of microscope, take a jar or a net, your cellphone for photos, and share them. If the Hashtag thing seems a little too complicated, just share them with the EEAC Google Group or friends via e-mail, or just share your microscope with strangers while you are at the pond… but most of all, have fun!

Jay

Biodiversity on my block

Posted by jholmes61 on July 31, 2016
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I was heading out of my apartment building, and down the block (151-150th Street on Broadway in New York) the other day whe I noticed this on the sidewalk. 


I posted it to Facebook and asked if any one could identify it. It generated lots of responses! I was impressed! Stag Beetle did come up a couple times. It is the head and thorax of a Lucanus capreolus – Reddish-brown Stag Beetle http://bugguide.net/node/view/3107 one report from a teacher friend from near by reported that they were all over 152 Street! Oooo a tip for a nearby expedition!

Then a couple days later, this, right out side our apartment door! Wildlife, mandible and hord!


So I started to think it might be fun to explore the biodiversity of my block. We have a variety of trees (in VERY small tree pits I might add) from the north: Gleditsia triacsnthos L. (Honey locust, New York City Trees, page 136), two Styphnolobium japonicum Schott (Chinese scholartree. New York City Trees, page 144), one Zelkova serrata Thumb. (Japanese Zelkova, New York City Trees, page 216) and last on the south a larger Styhnolobium japonicum (Chinese scholartree). The Chinese scholartree seem to host a couple “species” of lichen (in quotes because lichens are groups of three organisms based on some recent research, a fungi, a photosynthetic algae or bacteria and now a yeast).


The Candelaria concolor – yellow -orange-green, grainy – and Physcia millegrana – grey, fine lobes, grainy – are seen in the above photo. This is on the northern Chinese scholartree on our block, south side of the tree.

I collected a little bit of the Candelaria concolor and placed it in a bit of water and the did some reading for a couple hours while I waited for the creatures living on the lichen to reanimate.

I set up in the median park along this stretch of Broadway at one of the chess tables. 

You can see the median park in this photo and the trees along our block. You can also see the small size of our tree pit openings, they are really bricked in.

So here is the set-up:


A Swift FM-31 field microscope, a film can for the soaking specimen, a dropper,  well slides and coverslips. I found 5 or more Rotifer Genus: Philodina (Rainis, Kenneth G., Bruce J. Russell, Guide to Microlife, Franklin Watts, Danbury, CT, 1996, page 188) and one Tardigrade not sure, but probably genus Hypsibius.

I also had a couple other species visit while at the table:


A flesh fly (family: Sarcophagidae) came by for a drink of water around the edge of my coverslip, and a House Sparrow (Passer domesticus L.) hopped by.

The rotifer were certainly the highlight, swiming and inching along feeding and foraging. 

​​
I will keep my eye out for more species on our block to share. There are the usual feathered residents in addition to the sparrows, but I will try to get some photos before I list any. A great place to share observations like this is http://www.iNaturalist.org. Open an account and start sharing your local biodiversity, large and small.

Looking through Darwinian Glass

Posted by jholmes61 on July 19, 2016
Posted in: Uncategorized. Tagged: Darwin, microscope. Leave a comment

Ever science reading Brian Ford’s writing  on the single lens microscope and the Robert Bancks microscope that Darwin took on the Beagle I have had a fascination with the tools of this transitional period in microscopes and Darwin’s thoughtfulness about tools and observation.

I love providing people the opportunity to look through these tool at objects similar to those Darwin spent hours and days observing. I think these experiences are deeply inspirational and lead people to talking and thinking about all sorts of questions about the world around them.

I recently had the opportunity to acquire another Darwin period microscope, a Smith and Beck “Largest Best No. 1” microscope which is basically the binocular version of the Smith microscope that Darwin purchased on his return from the Beagle Voyage. Darwin’s Smith is on display in the Whipple Collection at Cambridge University.


One observation experience that I had the chance to set up with the Bancks and the Smith & Beck was with New York City librarians. They were at the Museum to learn about our Darwin Manuscript project and our rare books collection among other things. To set the stage I tried to replicate a little of the Beagle space, Darwin’s Poop Deck cabin. This was a bit impromptu, made a 4×6 ft foam core table top (recycled museum sign), used a few white boards for cabin walls and laid out elements of the cabin with masking tape on the floor and illustrations on the white boards.


For additional props in this chart room I added one Galapagos map pre-Beagle and one based on the Fitzroy Survey data, and a plankton net that I made based on Darwin’s notes. For a specimen under this Bancks microscope I placed some plankton collected from the Lake in Central Park. I also had a hydroid similar to one Darwin illustrated in his notebook, which he dredged off Bahia Blanca, South America, between September 29 and October 1, 1832.

In front of this area I set up a “lab table” with the Smith & Beck plus two US made scopes from the same period, a Zentmayer and a Queen. Both of these scopes are Pennsylvania made.


Lighting for these scopes was not period, I caved to the advantages of electricity. Under these compound microscopes we placed some “insectivorous plants” similar to those Darwin spent some time observing. We used Drosera (sundew) and Utricularia (bladderwort) under a variety of magnifications. Darwin was observing movement at the cellular level so he was using a pretty high magnification under the Smith for this. There are several pages of illustration of this in his manuscripts on the Museum’s website. Permalinks to some of these Darwin notes on Drosera cellular movement DAR 60.1: 79r, DAR 60.1: 81r

Above the hydroid in a jar and a sundew leaf on the Zentmayer.


Above is an image of a sundew tentacle taken through the Smith & Beck.


We were using the Bancks in dark field illumination mode which made the plankton sparkle!

It was a fun day, we chatted about the experience and the power of objects in education. In this case the combination of primary source documents and period objects bringing the documents to life in a variety of ways. So much fun and excited conversation.

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