Split Granite Foundation with a Mystery

A granite block from our foundation.
The foundation of our house is granite, which is common for old houses in New England. The basement walls are made up of about 6 feet of rubble including chunks of quarried granite and large round rocks all mortared together. At grade level there is a course of large rectangular granite blocks, each about 4ft long by 2ft high, that encompasses the original footprint of the house. This included a rectangular main house and an ell extension off the back which made the house an L shape. 

Each of the above ground blocks has a row of semi-cylindrical marks running across the bottom. These marks provide evidence of the technique used to cut these stones. At the time, I wanted to identify the marks on the stones partly in an effort to put them in an historical context, which I hoped would help me date the house. From my understanding now though, structures that were moved, as ours was, were normally given a new foundation in the new location which dates our stones to about 1858. 

I thought that understanding the chronology of stone splitting techniques would be pretty straightforward, but I was wrong (for more confusing dating of old objects, see Nails as well). I have written and rewritten this page several times as I've learned more and gained a better understanding of things I had already read and written about. Because what we know about an historic structure and it's intrinsic parts can only be based upon the physical and written evidence that has thus far been accounted for, there is a certain amount of irresolution that comes with the territory. In the words of James Garvin, author of, A Building History of Northern New England, "we have to take a number of somewhat overlapping and amorphous bodies of evidence, synthesize them, and try to come up with a defensible interpretation of the object before us" (personal communication, 7/26/2012). With that in mind I set out to outline as best I could the timetable of the evolution of stone splitting techniques from the 18th through the mid-19th centuries in New England. 

It is so rocky in this region that, from the earliest settlers onward, stones have always had to be reckoned with one way or another in order to make a living from the land. Farmers had to clear their land of trees and large stones to create and cultivate fields.Today, forests occupy 84% of New Hampshire, but in 1800 only 30% of the state was still forested due to farming and logging. That is why there are decrepit stone fences meandering through the woods. They are remnants of old, cleared farm land. As I drive along almost any road in New Hampshire that borders a forested area I can see these walls running through the trees. I had always wondered what they were doing there. 

The ability to split stones was critical to the New England farmer. As the old growth forests were replaced with crops and grazing land, creating boundaries between animals and your own crops and those of your neighbors became critical. Fences were created using either stone or wood or a combination of the two. Thomas Hubka wrote,
Today usually only the stone walls of this system remain, but they serve as a most fitting symbol for the effort to create the New England farm. No account of the region's agriculture can neglect the momentous toil that their making represented for the farmer. It was a staggering investment of labor conducted over a long period of time, usually by several generations on a farm. Perhaps the only positive advantage of new England's rocky soil was that the stones that were so laboriously removed from the fields could be used to make permanent walls. (Big House, Little House, Back House, Barn, pgs. 84-85) 
Barn foundation blast hole, Fremont, NH
By the early 19th century, quarrying and quarrying methods had been developed to allow for stone to be split into symmetrical, six-sided blocks for use in foundations, or as steps and posts, etc. Before this, however, splitting rocks was largely the farmer's domain. In the 18th century this was done by drilling a very deep hole into a stone, filling it with black gunpowder and blowing it apart. Stones that were split this way can show evidence of a deep half-round hole referred to today as a blast hole. Alternatively, a fire could be lit on top of a boulder, the heat allowing it to be split more easily with the blows of a mallet. The resulting rubble could be used for fences, wells, house cellars, foundations, chimneys or stone walls

Documentation of a method of splitting stones that would have left more shallow holes surfaced once or twice in the mid 18th century and again towards the end. This technique involved "drilling" a couple of round holes along the grain of the stone.  Metal, half-round wedges were then inserted with a longer shim in-between. The shim was hammered causing the stone to split. This process would have  produced round holes in an un-split stone or half-round holes along the grain of a split stone.

Reverend Samuel Deane, Portland, ca. 1800
(Maine Historical Society)
This method is described in the first encyclopedia of agriculture ever published in America, The New England Farmer, or Georgical Dictionary, written in 1790 by a Maine man, the Reverend Samuel Deane. His intended audience were farmers attempting to reduce the size of large boulders in their fields for uses around the farm.  Here is his description: 
Drill two holes in a stone, ranging with the grain, when that can be discovered by the eye. Then filling each hole with two semi-cylindrical pieces of iron, drive a long steel wedge between them. The stone will thus be split open. And commonly, very regular shaped pieces for building may be thus obtained. (p. 268-69)

The "plug and feather" method.
The technique that Rev. Deane described is an early version of what became known as "plug-and-feather." As I mentioned earlier, the evolution of stone splitting techniques gets confusing to me around the turn of the 19th century when stone began to be quarried and sold. As in any manufacturing business, the efficiency of producing the product was directly related to the profits. Previously, achieving a piece of six-sided relatively smooth, or dressed, piece of stone for use as a step, foundation block, etc. would have required an immense amount of handwork at a great cost of labor, so finding a way to split stone into regular shapes more easily and accurately would revolutionize the quarrying industry. 

The cause of my confusion about the development of quarrying techniques revolves around the "invention" of two similar methods of splitting stone, the "plug and feather" and the "flat wedge" methods. Both employ the use of force via wedges and mallets to crack stones apart but these two techniques are unique in the shape of their tools. 

Flat wedges used in the flat-wedge method
(photo: Stone Structures of New England)

A cape chisel
(photo: Stone Structures of New England)

The flat-wedge method employs a triangular, flat cape chisel to chip a hole along the grain of the stone. Three flat wedges are then inserted, the center wedge being longer, which is hammered until the stone cracks. When a cape chisel is used, a shallow rectangular mark is left on the face of the stone, thus, making it easy to identify the method used to split it. 
Cape chisel mark from a Fremont, NH barn.
There are two accounts of the development of stone splitting methods that revolutionized quarrying in Massachusetts at the turn of the 19th century. One comes from William S. Pattee's, "History of Old Braintree and Quincy," written in 1878. His account credits three Quincy quarrymen in 1803 for the development of a new granite splitting technique:
One Sunday in 1803, the first experiment in splitting stone with wedges was made by Josiah Bemis, George Stearns and Michael Weld. It proved successful, and so elated were these gentlemen on this memorial Sunday that they adjourned to Newcomb's Hotel, where they partook of a sumptuous repast. The wedges used in this experiment were flat, differing from those in use at the present time.
Although I don't know if they used a cape chisel, the method used by Bemis, Strearns and Weld appears to be the flat-wedge method.

The other technique in question is called "plug and feather" which produces half-round holes in the split stone. Some believe that the "plug and feather" method used in quarries was developed by a Mr. Tarbox around the turn of the 19th century. Charles Bulfinch, the iconic Federal architect, was hired to design the Massachusetts State Prison, which was to be built largely of stone. 

View of Massachusetts State Prison at Noon 
Avery & Dwight, Artists. Charlestown, Massachusetts, 1886

At the time, dressed, or flat-sided stone, was very expensive as a result of the hand work that was required to create it. The Massachusetts Governor from 1802 to 1806, Edward Hutchinson Robbins, believed he had found a way to reduce the price of dressed stone, thus cutting the cost of building the prison, when he discovered the work of a man known only as Mr. Tarbox. The source that brought Tarbox's apparent accomplishment to light was an 1859 paper given by Chief Justice Shaw before the American Academy of Arts and Sciences. Here is the excerpt that describes Robbin's discovery of the new method: 
Desirous of getting the stone for the prison on the best terms, and believing the prices high, though general, he thought much and conversed much on the subject. In that state of mind, and deeply interested in the subject of stone, he had occasion to pass through Salem in a chaise. In passing along a street, he noticed a building, apparently new, the basement story of which was of stone. He stopped to look at it carefully. In doing so, he perceived along the margin of each stone the marks of a tool at distances of six or seven inches apart. This was something new. He had never seen it on hewn stone. ... they were obtained in Danvers... by a man named Tarbox....
[H]e found Mr. Tarbox, in a small house, with a family, and with every appearance of poverty about him. After some little preliminary conversation, he asked Mr. Tarbox if he got out the stone in question, and if so, his method. He told him he had, and immediately proceeded to explain the process, and showed him his tools, his mode of drilling the holes, and inserting and driving the small wedges as above described.
Governor Robbins was at once struck with the idea that it was new and peculiar, and might be a very important invention. Governor Robbins did not say that he asked whether it was an invention of his own, or whether he had learned it of anybody else. But as it was new to himself, I think he was impressed with the belief that it was the invention of Tarbox.
Governor Robbins then asked him if he would consent to go up to Quincy and work two or three months and split stone in his mode, so that other workmen might practice it.... [H]e introduced Mr. Tarbox to several of the principal stone-dealers, and that it was not three months before every stone-cutter in Quincy could split stone with small wedges as well as Mr. Tarbox. Also that this improvement in the working of granite had in a very short time the effect to reduce the price to five eighths- of its former cost; that is, that the cost of the dimension stone wanted for the prison, which had before been $4.00, was afterwards reduced to $2.50, and other granite work in similar proportion.
As far as I know there isn't a clear written account of the method or tools that Tarbox used which would indicate whether the marks left on the stones he "got out" were flat or cylindrical. To know definitively I would need to know of a credible source one way or the other, or see the building foundations or stone blocks that are credited to he or his method. Shaw was very keen on giving the man who he believed had developed this revolutionary technique the credit he deserved:
It would be very extraordinary if an art of so much importance should be traced to a source so obscure as poor Mr. Tarbox, who seems to have been hardly conscious that he was doing anything extraordinary. It may be that this whole narrative rests on some mistake, and that a different origin for this art of working granite may be shown. If so, it is very desirable that it should be known to the public." In the face of these facts we must doubt the correctness of the following statement by Dr. Pattee in his "History of Quincy."
Justice Shaw goes on to say that the governor would have known if the process that Tarbox taught the Quincy quarrymen was already in use. This tells me that the process that was in use by Bemis, et al., and credited to them by Pattee, was the same method being used by Tarbox. Shaw says that "Mr. Bemis and his associates had copied the process from Tarbox;" but what Bemis et al. were credited with was the flat-wedge method not the plug-and-feather method. 
Surely a man of the intelligence possessed by Governor Rollins and holding the position of commissioner for building the State Prison would know as to whether the wedge-splitting process was in use before he introduced Mr. Tarbox. Then there is the important fact that immediately after Tarbox had taught the Quincy stone cutters his method they all used it with the result that the cost of dressed granite blocks was greatly reduced. It is quite clear to my mind that Mr. Bemis and his associates had copied the process from Tarbox and had on the "memorial Sunday" successfully split their first block of granite.
Mr. Tarbox had been hired to teach the Quincy men his method, in large part to provide the stone used in the construction of the Massachusetts State Prison. I don't know which, Tarbox or Bemis, et al. actually developed the revolutionary technique, but the stone did come from Bemis' quarry, which was apparently using the flat-wedge method to split their stone:

Description and historical sketch of the Massachusetts State Prison: with the statutes, rules and orders, for the government thereof.  By Massachusetts State Prison (Charlestown, Boston, Mass.). Board of Directors.

It's hard to imagine that if the plug and feather method was being used at Quincy that it wouldn't have spread to other parts of New England. According to James Garvin, former New Hampshire State Architectural Historian, it wasn't until roughly 1830 that the plug and feather method came into use. His information comes from the physical evidence he has found on datable structures, which is hard to argue with. He states that "although drills were used to create round holes for blasting with black gunpowder even in the 1700s, I have never found an instance of the use of plug drills and plugs-and-feathers to split granite by mere pressure before about 1825, and I can think of only two instances of the use of plug drills much before 1830."

Plug drills. 

By about 1830 the technique the plug and feather method was in use in quarries.  It employed a tool called a plug drill which had "a V-shaped point and was rotated slightly between each blow of the hammer, creating a round hole two or three inches deep and spaces every 3 or 4 inches.  Half round feathers, bent just at top to keep the shims from slipping into the hole, were dropped in with a wedge called a plug in-between. The plug was struck with a heavy mason's hammer until a cracking sound was heard. At that point the rock finished the job on it's own. (James Garvin, Granite Splitting Tools and Techniques).

The stones used in our foundation show the irregular marks of hand chiseling using plug drills. They could have come from any number of quarries in operation in New Hampshire in the mid-19th century. To me, knowing something about how the stone blocks that my house rests on were made not only gives it a life of its own, but gets to the point of owning an old house. It's nuances and quirks tell a story that would be a shame to miss out on. 
Commercial "plug and feather" quarrying marks on our granite foundation.
Written by Kerry Baldridge