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Changing Stories: Ovid’s Metamorphoses on canvas, 82 – The death of Numa, and a nymph turned into a spring

Posted: 02 Apr 2018 04:30 AM PDT

In the final book of Ovid’s Metamorphoses, King Numa, successor to Romulus the founder of Rome, had travelled to Crotona to learn the doctrines of Pythagoras.

The Story

After Numa had learned the doctrines of Pythagoras (an historical impossibility, as Numa lived between about 753-673 BCE, and Pythagoras between about 570-495 BCE and lived in Croton from about 530 BCE), he returned to Rome and established its early laws and institutions.

Numa’s success depended on his wife, the nymph Egeria. Although Ovid is not explicit here, other sources make the couple’s meeting a key step in the development of Rome, as Egeria was said to have dictated the first set of laws of Rome to Numa.

Inevitably, Numa grew old and then died. His wife Egeria was heartbroken: she left the city of Rome, and went deep into the forest, where her moaning disturbed those at the nearby shrine to Diana which had been built by Orestes. Sister nymphs tried to comfort her, but could not help. They told Egeria the tragic tale of Phaedra and Hippolytus – which I have examined in detail here – but this did not ease her grief either:
The grief of others could not ease the woe
of sad Egeria, and she laid herself
down at a mountain’s foot, dissolved in tears,
till moved by pity for her faithful sorrow,
Diana changed her body to a spring,
her limbs into a clear continual stream.

The Paintings

I have already shown and discussed paintings depicting the story of Phaedra and Hippolytus. Those showing Numa and Egeria are not plentiful, nor are they particularly straightforward.

poussinnumapompilius
Nicolas Poussin (1594–1665), Numa Pompilius and the Nymph Egeria (1631-33), oil on canvas, 75 × 100 cm, Musée Condé, Chantilly, France. Wikimedia Commons.

Nicolas Poussin’s Numa Pompilius and the Nymph Egeria from 1631-33 is thought to have been painted for his long-term friend and patron Cassiano Dal Pozzo (1588-1657), a scholar and patron of the arts, who was secretary to Cardinal Francesco Barberini.

It shows the meeting of King Numa, at the right, with Egeria, at the left, as she was being entertained by a young man with a lute, who may signify the Muses who apparently inspired Egeria to provide the laws of Rome. However, Numa hasn’t come equipped with any means of recording them, suggesting that this wasn’t the occasion on which Egeria dictated those laws.

gianinumapomilioegeria
Felice Giani (1758–1823), Numa Pompilius Receiving from the Nymph Egeria the Laws of Rome (1806), oil on canvas, dimensions not known, Palazzo dell’Ambasciata di Spagna, Rome, Italy. Wikimedia Commons.

Felice Giani’s much later painting of Numa Pompilius Receiving from the Nymph Egeria the Laws of Rome (1806) shows that process of dictation in full swing, with Numa working through scrolls, which are then transcribed onto the tablets of stone seen at the left. The nymph is the one sat on a throne, and is clearly in command, wagging her index finger at the King of Rome.

checanymphegeriadictating
Ulpiano Checa (1860–1916), The Nymph Egeria Dictating to Numa Pompilius the Laws of Rome (c 1886), oil on canvas, 300 x 200 cm, Museo Nacional del Prado, Madrid, Spain. Image by Poniol60, via Wikimedia Commons.

Ulpiano Checa’s The Nymph Egeria Dictating to Numa Pompilius the Laws of Rome (c 1886) offers a similar account, with King Numa sat writing down the laws on scrolls of paper using a reed pen. Egeria is quite different, though, and appears a simple and very naked nymph.

claudelandscapeegeria
Claude Lorrain (1604/1605–1682), Landscape with the Nymph Egeria Weeping Over Numa (1669), oil on panel, 155 x 199 cm, Museo di Capodimonte, Naples, Italy. Image by Mentnafunangann, via Wikimedia Commons.

The only accessible painting which shows Egeria’s grief following the death of Numa is Claude Lorrain’s Landscape with the Nymph Egeria Weeping Over Numa from 1669.

Unfortunately, great confusion has arisen over the true nature of this painting, as two images of details have been published on the internet purporting to be quite different and complete paintings. Claude’s painting itself is something of a puzzle too, and the result is that many of the images shown online of this work make no sense at all.

The full painting, shown above, shows a group of people and dogs in the left foreground, set in an idealised classical landscape on the coast.

The detail, shown below, reveals the five women in that group. Second from left is most probably the figure of Egeria, although there is nothing to show her profuse weeping or grief. One of the three women to the right of Egeria is Diana, with her spear, bow, arrows, and hunting dogs. It is unclear whether she is on bended knee, or stood behind holding the leash of one of the dogs.

claudelandscapeegeriad1
Claude Lorrain (1604/1605–1682), Landscape with the Nymph Egeria Weeping Over Numa (detail) (1669), oil on panel, 155 x 199 cm, Museo di Capodimonte, Naples, Italy. Wikimedia Commons.

More puzzling is the gesture of the woman (Diana or nymph) who is kneeling on one knee. Her left hand points towards Egeria, and her right is pointing away, towards the buildings down by the water. Her meaning is obscure in the context of the story of Egeria.

Whether this painting by Claude shows the story of Egeria and her grief over the death of Numa must surely be in doubt, and the evidence bears careful re-examination.

The English translation of Ovid above is taken from Ovid. Metamorphoses. Tr. Brookes More. Boston. Cornhill Publishing Co. 1922, at Perseus. I am very grateful to Perseus at Tufts for this.

Inside iCloud Drive: Pushed updates, that syncing feeling

Posted: 02 Apr 2018 12:00 AM PDT

The two common scenarios in which iCloud Drive appears to become stuck, and cause long waits for users, are uploading files, and propagating such uploads (and other changes) to other clients connected to the same account.

In my previous article I looked at the steps involved in uploading. This article looks at propagating those changes to other clients, but stops short of them downloading new or changed files.

To investigate this, I ran my tool Cirrus simultaneously on two Macs connected to the same iCloud account, on the same local network. I ran the standard 1 MB upload test in Cirrus on one, then watched for that new file to be propagated via iCloud Drive to the other. I did this with privacy disabled, and examined both log extracts, and a full log extract on the recipient Mac, using Consolation. I’ll refer to the uploading Mac as A (running 10.12.6), and the syncing Mac as B (running 10.13.4).

Mac A’s progress icon went very quickly to over 90% complete, as it usually does, then paused before completing within 5 seconds. The last delay coincides with the phase identified by CloudDocs as sync down, which runs after the actual upload is complete, and is described by CloudKit as FetchRecordZoneChanges.

This phase started at 4.207 seconds time elapsed, and completed at 4.462 seconds, at which point Mac A was finished.

Receipt of the push notification from APS to Mac B of changes to iCloud Drive was logged at 4.310 seconds time elapsed, well before the completion of the final phase on Mac A.

iCloudOpsOverview

The log entry first recording the push notification is worth noting:
04.310 com.apple.apsd courier Stream processing: complete yes, invalid no, length parsed 249, parameters {
APSProtocolCommand = 10;
APSProtocolMessageExpiry = "1970-01-01 18:12:15 +0000";
APSProtocolMessageID = <e9c74616>;
APSProtocolMessagePriority = 5;
APSProtocolMessageTimestamp = 1522602544155347565;
APSProtocolPayload = <…>;
APSProtocolToken = <…>;
APSProtocolTopicHash = <…>;
}

I hope that the expiry given means that the message never expires.

This was then interpreted by apsd as:
04.311 com.apple.apsd courier-oversized Received message for enabled topic 'com.apple.icloud-container.clouddocs.com.apple.CloudDocs' onInterface: NonCellular with payload '{
ck = {
ce = 1;
cid = "com.apple.clouddocs";
fet = {
dbs = 1;
sid = "subscription/com.apple.CloudDocs";
zid = "com.apple.CloudDocs";
zoid = "…";
};
nid = "…";
};
}' with priority 5

Key events in its processing include:
04.311 apsd asked to store incoming message <…> with guid … environment …
04.311 com.apple.apsd courier Stream processing: complete no, invalid no, length parsed 0, parameters (null)

The next entry is important, and records that low-priority notifications are then deleted, which could of course explain some problems:
04.311 apsd deleting low-priority incoming messages for topic com.apple.icloud-container.clouddocs.com.apple.CloudDocs environment production
04.311 apsd APSMessageStore - APSIncomingMessageRecordDeleteMessagesForTopic com.apple.icloud-container.clouddocs.com.apple.CloudDocs 1 environment production
04.316 apsd APSMessageStore - New message record [<…>{}] has ID [8726].
04.316 apsd calling completion block for incoming message …
04.316 com.apple.apsd courier Sending acknowledgement message with response 0 and messageId <…> (3922150934)
04.317 com.apple.apsd courier _notifyForIncomingMessage … with guid …
04.317 com.apple.apsd connectionServer Dispatching low priority message: <xpc object>
04.317 apsd Looking up connection on peer: … found …
04.318 com.apple.apsd connection bird ApplePushService … Delivering message from apsd: … … com.apple.icloud-container.clouddocs.com.apple.CloudDocs
04.318 com.apple.apsd connection bird ApplePushService … responding with an ack for message with guid …

At this stage, bird has received the pushed notification, and this is announced by CloudDocs at the start of the sync sequence:
04.318 CloudDocs [NOTICE] received a push for client zone com.apple.CloudDocs
CloudDocs then starts the sync down, which is announced by bird.

This triggers a long dialog between cloudd and CloudKit to perform the sync down:
04.322 CloudKit starts CKFetchRecordZoneChangesOperation
which is then echoed by cloudd as fetch-record-changes.

Next, CloudKit starts CKDFetchRecordZoneChangesOperation, announced by cloudd as db-operation, and CloudKit starts CKDRecordFetchAggregator.

cloudd announces url-request then c2-request-task, and at this stage DuetActivityScheduler (DAS), one of the main activity scheduling and dispatching services, becomes involved, submitting activities for this to one of its activities groups, com.apple.cloudkit.BackgroundConnectionPool. Note that this is scheduled to a pool of background connection activities, which may explain why sync down can become greatly delayed.

After cloudd announces url-request-transmission, there is a loop to fetch the new/changed records for iCloud Drive. This runs in sequence:
04.830 cloudd announces fetch-records
CloudKit starts CKDFetchRecordsOperation
cloudd announces decrypt-records
CloudKit starts CKDDecryptRecordsOperation
cloudd announces db-operation, then starts its state transition sequences
04.849 CloudDocs [INFO] got a record
CloudKit finished CKDFetchRecordsOperation
and then recycles with cloudd announcing fetch-records again, until all the records are fetched.

Once those are completed:
04.863 bird announces did-sync-down
CloudDocs [NOTICE] received 2 edited items from the cloud for com.apple.CloudDocs
CloudKit finished CKDFetchRecordsOperation, CKDRecordFetchAggregator, CKDFetchRecordZoneChangesOperation
04.868 bird finish-changes
CloudKit finished CKFetchRecordZoneChangesOperation – sync down (push triggered)

This completes the sync-down, and the first run through the iCloud progress icon. At this stage, iCloud Drive shows the new/changed items, but they have not yet been downloaded to Mac B. That sequence starts with the announcement:
00:04.871 CloudDocs [NOTICE] we will now download new documents automatically because the account contains less than 5.37 GB
00:04.913 CloudDocs [NOTICE] downloading 1 documents in com.apple.CloudDocs

then bird calls dl-content and client/fetch-records, for CloudKit to download (opportunistic). I will analyse the download process in another article shortly.

The sync down sequence on Mac B is summarised in the following chart. Note that MMCS is not involved at all (judging by its complete lack of log entries) in this sequence, as no bulk transfers take place.

iCloudOps2

This suggests several good reasons for a Mac or iOS device failing to sync promptly:

  • iCloud may not push the notification promptly
  • the pushed notification may not be received, relying on iCloud to send another when that first message passes unacknowledged
  • the pushed notification may get deleted by higher priority messages
  • bird, CloudDocs, or CloudKit may stall part way through the sync down sequence.

It should be fairly straightforward to distinguish between these using the log obtained with Cirrus.

These also explain why uploading a file to iCloud Drive could clear a sync down failure, by forcing a fresh sync down of its own. That should include all earlier changes too.

My concern over performance is the involvement of DAS and the use of its pool of background connection activities. If that pool is busy, iCloud Drive sync down could be delayed considerably. There doesn’t appear to be any way to influence that, which is a design decision on Apple’s part.